How do I record guitar / bass on Sony ACID music studio 8?

I just got the program, trying to figure it out, more or less. And, apparently, from what I gather, ACID doesn't want me to use my own riffs or anything, but instead wants me to load pre-recorded tracks on to the program, and then chop away until music happens. That's not what I want. So, how do I like, record my bass and guitar riffs on to this program?