As it is a Swyama Siddha Hanuman Mantra it does not have to get chanted for a fixed number of Mantra Repetitions for being able to use it. Specific worship and rituals and rules regarding direction, sitting down mat, and counting rosary are not recommended for chanting this Hanuman Mantra. https://www.youtube.com/watch?v=ufkmD95y7fE&t=32s