As it is a Swyama Siddha Hanuman Mantra it doesn't have for being chanted for a hard and fast range of Mantra Repetitions for having the ability to use it. Particular worship and rituals and rules about course, sitting mat, and counting rosary will not be advised for chanting this https://www.youtube.com/watch?v=ufkmD95y7fE&t=32s