At the least, you will want to practice pull ups dips and hanging leg raises. I also suggest rollovers and muscle up negatives. Id say a reasonable timeframe to get a muscle up for someone who is reasonably fit starting out and pretty dedicated is 2-6 months. Could be longer, or even shorter. So don’t get too set on a deadline. I think I was training for about 5 months before I got a muscle up on rings.