As this is the Swyama Siddha Hanuman Mantra it does not have to generally be chanted for a fixed number of Mantra Repetitions for having the ability to utilize it. Special worship and rituals and rules about direction, sitting mat, and counting rosary aren't recommended for chanting this Hanuman Mantra. https://www.youtube.com/watch?v=ufkmD95y7fE&t=32s