Get a camera kit to connect the controller to the iPad. Depending on the controller, you may may need a powered usb hub - M-Audio keystation is low power, but Akai Mini needs more than the iPad will put out, for example.

I like the BeatMaker3 program, as it is good as a looper for a backing track, as well as being a host for Audio Units.

Lorentz is a nice analog emulator (similar to Juno 106), KQ Dixie a SysEx compatible DX7 emulator , and bs-16i a soundfont rompler.

Later you can get other instruments and additional effects, but I think those are a good starter kit. Also, the Yamaha home PSR keyboards, even the $200 ones, transfer audio as well as MIDI over USB, so you might look at one of those.

As others have pointed out, learn some music basics, such as what a I IV V vi (or i iv v VI) chord progression is, as well as major vs minor keys / scales / modes and such.

Disclosure: I’m a hobbyist, so don’t take this as career advice :-)

E.g. - https://soundcloud.com/rob-anderson-104336556/sets/cassiopod... - many of the songs have notes on the setup used. (Yeah, not quitting my day job)