>>2432805Bottom bracket standards are all over the place.
Shimano and SRAM are generally interchangeable, for example I have SRAM shifters on Shimano derailleurs.
You have 3 options of mounting your cassette to the rear hub, and you need to have a derailleur and shifter to match however many gears you have, otherwise you'll be unable to use all your gears, or keep dropping the chain.
Rear wheel will be built offset to keep tyre centre according to the size of cassette you're using.
There's also a variety of axle options.
Brake discs have 2 main mounting types, but just buy according to whatever hub you get, either bolt on or splined.
Just start with your frame and work from there.
There's quite a lot of homework to do, but it's entirely achievable.
