How to chant the mantra Nam Myoho Renge Kyo?

I am a Hindu by birth. I am a huge devotee of Lord Buddha as he is considered a god in Hinduism. I wanted to know more about the Buddhist mantra Nam Myoho Renge Kyo. What is the best way to chant it? Can I chant it anywhere and at anytime? I have previously been chanting the mantra at least 108 times a day for the past 4 months but I have yet to see any of my desires fulfilled. Is there a specific count when desires are fulfilled? I apologise, I am new to Buddhist methods of worship, but I want to do so with Buddha. How can I have my desires fulfilled by that mantra? Thank You.