That escalated quickly.
Look, I agree the documentation is far from perfect. That's why I put as much effort into improving it as I have (and still hope to do more, someday when I'm not snowed under with homework and other concerns). Artwork is one place where it's fairly weak and out of date precisely because there's so much to cover.
At the same time, one of the purposes of the wiki is so that we don't have to write the same explanations over and over again. Frankz and phred are both very active, helpful forum members but we all have limited time. The question about tracks from the same album being separated IS addressed in the FAQ. I know because I wrote it. The same methods should work for combining multi-disc albums that are being separated by disc. If you've tried those things, then come and ask for more help. The more detail you can give us about what you've already done, the better.
The Playlists page covers creating or adding to playlists by drag & drop. (Although I just discovered that it's even easier with the Playlist Directory than with the left sidebar.)
MusicBee does have a feature that allows you to merge albums by drag & drop, but it has to be enabled in Tags (2). I also can't say for sure if it will have exactly the result you want.