In Musicbrainz, recordings (the tracks on a release) are linked to works (compositions). Information about composer, arranger, instrumentator, orchestrator, lyricist, librettist, translator or publisher is added to works. As different versions are recorded from the same work, there are often more recordings linked to one work. So there's a chance that even if you've added a new recording when you added a release, a corresponding work was already in the database. Now we'll link the recording from the previous post to a work.
First, go to the "Works" tab on the artist page. In this case, our artist doesn't have a work for the recording "De beer", so click on "Add work".

In the next page, there are 4 fields that can be filled, but only the name field is compulsory. Adding a comment is useful for disambiguation, that is, if the artist has multiple works with the same name that should not be merged (more info. ISWC is an ISO standard for identifying works, but not all (most?) works don't have one. The type of work is only relevant to classical music. As usual, an edit note with proof of your edit is appreciated. Click "Enter edit" to complete this phase.

Now we have a work and we already had the recording, but we'll have to let Musicbrainz know they are related to each other.
Go to the page for the recording and click "Use in a relationship".

Go back to the page with the work and click either "Use in a relationship" or "Create a relationship with [recording name]", whichever is displayed.

On the next page, select the correct relationship. Tick "cover" if the recording you're linking is a cover version of the work, but that's not the case now. Adding an edit note is again appreciated, but this edit is so obvious that it's a bit superfluous.

Now that we've created the work and linked it to the recording, it's time to link the work with the artists that composed it, wrote its lyrics etc. Go to the work page and click on "Relate to ...". Type in the name in the pop-up box etc, you'll know the drill by now.

That's it. There are a lot more things you can add, but this should get you started for a while. Have fun!

Information like performer, (re)mixer or producer are linked between recordings and artists. Adding such a relationship between a recording and an artist is pretty straightforward. First, open the artist you want to add to the recordings in a new tab or window. Next, click "Use in a relationship" in the right panel on the artist page.

Next, go back to the tab or window with the release and refresh the page. When the page has finished loading, there should be a "Relate <artist> to recordings" link to the right. Click the link to go to the Create Relationship page.

On the next page, select the type of the relationship you want to add in the drop-down menu (1). Under recordings, you can either select individual recordings to add the relationship to, or select them all with the checkbox at 2.

Enter an edit note with proof of your edit and hit Enter edit.

If you want to add an Advanced Relationship to a specific recording, go to the recording by clicking on an entry in a releases tracklist, and on the recording page, click "Relate to ..."

In the pop-up dialogue, type the artist you want to relate to the recording and select the artist from the list. Remember that if you created the artist very recently, you have to click "Not found? Try again with a direct search." for it to appear. Click "Create relationship" and on the next page, specify the relationship, fill in the Edit Note and enter the edit.

Index:
Add release
Adding relationships to recordings
Adding works and adding links to recordings and works

Add release

Go to the artist's page and if the release you want to add is not yet there, click "Add release". Adding a release group first is not necessary, because it is automatically generated when the release is entered into the database.

The first tab of the release editor, "Release Information" is meant for general information about the release. At the bare minimum, the artist and release title have to be filled in. If the release title is the same as the release group title, the field can be left blank, because the new release group will get the same title as the new release.
The release used in this example is a collaboration of two artists, but we started from the artist page of only one of them, so the artist has to be changed to properly reflect the collaboration. To do this, click on the double arrow to the right of the artist field.

In the balloon on the right, click the green plus next to "Add Artist Credit". Because the collaboration is called Kubus & Sticks, change Sticks in the first entry to Kubus and enter Sticks in the second entry. As you type, Musicbrainz will search the database for the artist and present you with a list of possible matches. If you have added an artist to Musicbrainz very recently, it will not yet appear in this list. In that case, click "Not found? Try again with direct search." Musicbrainz will provide you with a new list with the correct artist.

The other fields on this page should speak for themselves. As a final note, the annotation field is for any information about the release that does not fit in Musicbrainz' data structure. Examples are notes to future editors (for example about things you're unsure of) or links to further information about the release that cannot be represented by any advanced relationships. The disambiguation field is useful if there are several releases by an artist with the same release title (like greatest hits compilations). If there is no danger of confusing similarly named releases, leave it blank.

When you're satisfied with the information on the page, click Next. The next tab in the Release Editor, Release Duplicates is usually skipped if there are no similar releases in Musicbrainz, which brings us to the Tracklist tab.
There are two ways of entering the tracks of the release, by using the Track Parser (1) or by adding a number of empty tracks to the table and filling them. To do this, type the number of tracks you want to add and click the green plus (2). Tracks are entered per medium. Because this release is a download, there is only one medium. Extra media are added by clicking Add Disc. The Format of the medium is in this case Digital Media. Because this is a single medium release, the Disc Title field is greyed out.

We'll use the Track Parser because that is the fastest way to enter an entire tracklist. You can type the tracklist in the field or copy/paste one from an online source. When you're done typing or copy-pasting, click Parse Tracks to fill this release medium with tracks and Done to close the Track Parser.

In this release, track 5 has a featuring artist. In the past, featuring artists in Musicbrainz were appended to the track title, but with the implementation of artist credits, featuring artists should be added to the track artist. Tick the check box next to Artist (1) and click on credits (2) next to the track we want to change.

The new dialogue is similar to the release artist dialogue in the Release Information tab. Click Add Artist Credit and change the Join phrase to " feat. " (note the spaces around the word). Type and select the featuring artist.

When you're happy with the contents of the page, click Next to go to the Recordings tab.

Whereas the tracklist represents the list of tracks as you find it on the back of the album you just bought, recordings represent the actual audio you hear when you put it in your stereo. Recordings can appear on many releases, for example singles that appear on many compilations. By default, the Release Editor will create new recordings. If you think a recording on the release is already in Musicbrainz, click Change next to the recording and click the magnifying glass to search for it. If it is on the list, select it and click Done. Beware though, just because a track by the same artist has same name, doesn't mean it should be merged. If you're unsure, opt for a new recording.

Click Next and if you entered all artists correctly, you should immediately go to the Edit Note tab.
On this tab, check all the information for errors and if you're satisfied, enter an Edit Note.