Start with opening individual music files or directories by dragging them into the left-hand pane. Picard will read the metadata from each of the files and unless they have been tagged before, the files will be deposited into the "Unmatched files" folder. Files that have been tagged before and contain MusicBrainz track identifiers will open up in the right-hand pane as a part of its release.
Once Picard finishes processing the files, press the "Cluster" button. Picard will attempt to group the files into album clusters by examining the metadata and clustering files that appear to belong to the same album. Files that are not matched into album clusters will remain in the "Unmatched files" folder.
Select the cluster or file you want to lookup and use the "Lookup" button in the toolbar.
Picard will query MusicBrainz with your existing metadata and attempt to find the best possible match.
Instead of using release-oriented and metadata-dependent lookups, Picard can try and tag your files as single files (rather than a cluster) based on their audio fingerprint. If you select a set of files in the left-hand pane and click "Scan", Picard will find AcoustIDs for your files and query MusicBrainz to find a track that matches them.
If you want granular control over how your files are being tagged, or the above methods provided inaccurate results (or no results), the alternative is to manually lookup and choose the correct release(s) for your files.
Select the cluster or file you want to lookup and use one of the lower "Lookup" buttons in Picard. This opens the MusicBrainz website with a list of possible matches for your files along with details on what sets them apart, you can also disregard the lookup results and manually search for the appropriate album using the search box. Once you've found the correct album, click on the icon in the album title and Picard will load that album and its tracks into the right-hand pane for you to drag clusters/files onto.
The tracks in the right-hand pane will start out with a musical note icon, and as the tracks become associated with your files the icons will change to one of the following:
You can drag whole directories, multiple files or album clusters onto albums and Picard will attempt to match the dragged files to the album. Any track that doesn't match up well enough, will be added to an "Unmatched Files" sub-folder specific to that album. You can drag files out of this folder and into the right slots in the album to fix up the files that Picard couldn't get right.
Once you've finished matching up your files to albums in the right-hand pane, right click the album and select the release event that corresponds to your specific release and then click the 'Save' button to save that track/album. Depending on your settings this may move the track to a new directory and/or rename the track according to its metadata. Take a look at the options dialog to fine tune your settings.
Once a file is in the right-hand pane the metadata that will be written by Picard can be viewed and edited if necessary. Left click the file and use the metadata comparison table at the bottom to view and, if necessary, edit the metadata. Remember to re-save the file(s) if you edit the metadata!
Once you've saved an album and/or want to remove it from view, right click the album in the right-hand pane and click 'Remove'.
Yes there is!
A lot of Picard's power is in its extensive drag and drop features. Try some of these operations: