I'm trying to create new items, spells, sub-classes, etc, but it's not a very user friendly interface. I can't find any compendium or database that has a list of all the macros that I would need to type and format so that they function properly.

Does anyone here have any experience with this, and could help me out?

You want to take a look in the Homebrew and House Rules subforum, especially the pinned threads.

Here’s an FAQ I put together for folks, I think you’ll find it helpful: (https://www.dndbeyond.com/forums/dungeons-dragons-discussion/homebrew-house-rules/131411-a-homebrewers-how-to-faq). Included are links to all the best threads and articles DDB has for homebrewing, as well as lots of other practical information. If you have any further questions you can ask me there and I’ll do my best to help.