I personally use a couple of different programs, but they can pretty expansive. Mixcraft is fairly affordable, easy to use, and comes equipped with a pretty large library of loops, which means you create stuff right off the bat without any recording material to hand. Fruity Loops is another great one, probably the most popular, with an extensive array of features and loops. However, I think it's a good deal more expensive. I have used both, but I tend to work it in conjunction with my actual recordings. In terms of learning how to use these types of programs, I think the best thing to do is to experiment for yourself. That's how I did it, and it means you become accustomed at your own pace. If you're wanting to record your own content, then that's a bit trickier. I was lucky in that a had the use of a little studio (see: a room with a couple of mics), but you can purchase some good and fairly inexpensive mics which will do the job just fine.
I'd recommend downloading some trial music software and playing around in each, working out the differences and seeing how comfortable you are with each of them, and then move on from there.
FL Studio demo & full installer download
Mixcraft 7 | Pro Studio | Recording Software | Acoustica
Avid | Pro Tools Family