As that is a Swyama Siddha Hanuman Mantra it does not have to generally be chanted for a set number of Mantra Repetitions for being able to use it. Unique worship and rituals and principles regarding way, sitting mat, and counting rosary aren't advised for chanting this Hanuman Mantra. The https://www.youtube.com/watch?v=ufkmD95y7fE&t=32s