>>12034985Check out chemistry libre texts.
Dont pay for books, you can get claden org chem, Shriver and Atkins inorg chem and atkins phys chem online for free. That's a bulk of the foundation for undergrad.
I'd start with Org chem as I think it is easiest and the most interesting. By the time you get to retrosynthesis you can just sketch/find a molecule and work out how youd make it which is fun.
Only way to master this stuff is problem solving.
Learn the periodic table.