As it is a Swyama Siddha Hanuman Mantra it doesn't have for being chanted for a fixed number of Mantra Repetitions for being able to utilize it. Special worship and rituals and rules about path, sitting down mat, and counting rosary are certainly not encouraged for chanting this Hanuman Mantra. https://www.youtube.com/watch?v=ufkmD95y7fE&t=32s