the answer to your question can be as long as an answer to "how to build a car".....
I don't mean to diss you, I am lost in this audio recording world myself, too
you got so many things to consider, here are some examples:
1) Instruments: keyboard, modular, synth keyboard, drum machine...ect
2)Mics+mic pre: this covers about 100000000 products out there that people argue about everyday
3)Something to record on: Hard disk, computer (PC/Mac), ADAT, tapes..so on.
4) If you go computer, there are softwares to think about
If you don't plan on spending more than a couple hundred bucks, I would start with the instruments and mics. If you know how to use them or own them already and don't wanna spend a whole lot, use your home stereo/boom box (and hopefully it has the overdubbing function) and track one thing at a time on regular tapes. The quality will be bad, but, you get to produce your won music at least...
Or, get a cheap software+soundcard and mess with it
Now, if you got lots money, some experts will show to the way to a pro sound