You will almost certainly need :
- Some recording software. There's loads available, and most will have cut-down or demo versions for you to try before you buy.
- a decent quality audio interface to get the sound in and out of the computer
- a computer that's fast enough to deal with it all
- a bit of luck that it will all work well together (sometimes, with the best will in the world, it just doesn't!)
Your first step is probably to find an interface. If you say what computer you have, it will help people recommend something.