As this is the Swyama Siddha Hanuman Mantra it doesn't have to generally be chanted for a fixed number of Mantra Repetitions for having the ability to use it. Specific worship and rituals and regulations regarding path, sitting mat, and counting rosary usually are not proposed for chanting this Hanuman https://www.youtube.com/watch?v=ufkmD95y7fE&t=32s