As this is the Swyama Siddha Hanuman Mantra it doesn't have to become chanted for a fixed number of Mantra Repetitions for having the ability to use it. Specific worship and rituals and rules with regards to direction, sitting mat, and counting rosary will not be recommended for chanting this https://www.youtube.com/watch?v=ufkmD95y7fE&t=32s