The double stroke roll is a pretty big deal, such a big deal that there are three entire workouts right here for this one rudiment (one for each of the major differences in approach relative to tempo). This is also one of the 12 Gateway rudiments & there are three different workouts over there to do as well. (Holy 6 exercises for one rudiment Batman!) Doubles aren't easy, or simple and there's a big difference in the nuance & touch between those who can play doubles well and those who wish they could. This may well be your best opportunity & strategy to join the club of those who can play great doubles. It's a happy place!