Hello kwg2371, I use a program that I bought some time back for pretty darn cheap, I was a beginner as well . I wasn't expecting it to be so great but it really surprised me and produced a solid sound. I got it .. Its also fairly intuitive for my controllers and pads .. I got it down and used it with pretty fair efficiency in a few days.. you can make my own beats/ riffs etc on and control tempo/speeds, and all the things you mentioned and more.. from this website
I also am a big fan of EDM and which is mostly what I make, so I really hope this helps you as much as it helped me.