Question or Help?

So if I buy Tasha's Cauldron of Everything do I get the class info to easily drop-down info to a characters sheet? Thought a Pro subscription would open stuff up from the books, nope! Still don't know what Pro does other then get rid of adds? & gives few other things for GM's guess I'm to new make full use of the service.

Pro gives you access to features of Roll20 (transmogrifier and access to the api to use api scripts being the primary draws of the pro subscription). You also need it to test character sheet code if you are writing a new sheet (or editing an existing one) for the platform.  A subscription has nothing to do with compendium content, since what you are talking about then is content owned by a publisher (not Roll20). Buying a book that adds compendium content will make the content from that book available in the compendium in game, as long as that source isn't disabled in the game settings.