Then you would click on the single track and edit the Album tag to match the new album name. Exactly the same so that MC groups it with the other tracks in that album. Note that a track can only have one album it belongs to. If you want to create alternative list or your own 'Albums' that is what playlists are for. A track can appear in any number of playlists, while a track can only have one album; usually what is was published as.
To move unassigned tracks into an Album you can change the Album tag one by one or select multiple tracks (with Shift, Ctrl etc.) and then change all of them at once by updating the tag. MC helps by showing close matches which you can select with mouse or arrow kes then hit enter. If you are coming from itunes the early version were to be notorious for lossing tags on import, I used to have separate piece of software called 'Rinse' to clean up itunes, discointued a long time ago.