Workout Timer App helps to set the time for a workout of m sets with each set consisting of n exercises for a certain period of time.
For example it helps to time a lower body workout of 3 sets with each set consisting of 3 rounds say squats, Jumpings and Burpees for 45 seconds each with 15 seconds of rest time in between.
It has a option to play the beep while working out and also alerts at the the end of each round of workout and rest time.