If you never recorded anything...., but ok with iphone, My suggestion:

Get an MultiTrack DAW app for iphone or similar. The one that can record multiple tracks.
You can get multitrack apps from $3-$10.

Get a simple interface like iRig (looks like AA battery, slightly bigger) that you connect to microphone and the other end to iphone. Or even skip the interface and microphone and record multiple tracks using iphone mic, just to see if you are ok with it.

I would say that would be your easiest and cheapest way to get into the magic of recording audio.

If you feel comfortable, and you want to learn more, you can use same interface (if you get one) for PC and explore the endless galaxy of computer world accompaniment / recording software and peripherals.