How to Use Works
MusicBrainz works (generally) represent specific compositions, or parts of them. For example, a specific song is a work: Hurt represents the composition by Trent Reznor, regardless of whether it is performed by Nine Inch Nails, Johnny Cash or any other artist.
Works allow us to group together all performances of the same composition, and to only enter composer/lyricist credits once. By linking recordings to works, you can also easily mark cover versions.
Relating Recordings to Works
Works should generally be linked to recordings with the "recording of" relationship: see the documentation for that relationship to find more info on when each of the attributes should be used. When linking a cover recording, it's especially useful to also link the work to the original recording, if it isn't already linked (for example because you've just created it, see how to create works below).
Relating recordings to works is very simple: you can either relate all recordings on a release to works using the relationship editor, or do it from the recording page with the Relate to... option. If you're working on a specific artist, you can also relate the same work to multiple recordings at the same time from the Recordings tab of the artist, using the Batch-add "performance of" relationships userscript - but be careful to only relate the right recordings to each work!
Creating Works
Add the name of the Recording, the type and the lyrics language and then create the Work. Copy the URL of this new Work to your clipboard.
Go to the Recording page for the original Recording (i.e. the composer of the song) and relate it to the Work (the easiest way is to click Relate to... and then paste the URL of the new Work into the box), then pick "is a {partial} {live} {instrumental} {cover} recording of..." and DON'T check any of the optional checkboxes. This will define the original Recording as being the original for the Work too. This sounds a bit confusing, but it's necessary.
Once this step has been completed, then go to the Recording page for the cover version (from the Release that you originally added) and follow the same steps as above but this time tick the checkbox for cover version.
