I'm telling you this because I will no longer be using audiotool, as I'm getting fl studio tomorrow, so I thought I'd share it all with you:) you can check out my songs and get ideas from them if you like!
I use a website called (link is only visible to registered users) to make samples. I then save them as loops, and in port a sample on audiotool and put them all together. It's very simple once you've got the hang of them both.