One has to select and chant any one of the two Mantras from the Rama Rahasya for 11 Rosaries daily using a Tulsi Beads Counting Rosary at dusk.
Other than this there are no rules or prescriptions attached to the chanting of both these Shri Ram Mantras.
Mantra: ।। ॐ नमो भगवते रामभद्राय ।।
।।Om namo Bhagvate Rambhadraay ।।
।।ॐ रामभद्राय नमः ।।
।। Om Ramabhadraay Namaha ||
Note- Both these Mantras give the same results, vibrate to the same frequency and are essentially chanted for the same purpose, which has been mentioned above.