Relaxing the brain through Mantra is one of the methods of increasing perception. The superficial aspects of thoughts, emotions or desires which are not needed within the mind and which need to be expressed will be swept away by the Mantra. A proper Asana or posture should be selected and maintained for the duration of the practice so that there is no movement to distract the concentration.
If you are feeling uncomfortable while doing Yoga Asanas by yourselves, do not push yourself. It will be helpful to actually sign up for some Yoga Classes where a professional teacher will guide you through each Asana and will make sure that you are doing the exercise correctly.
In Bhakti Yoga, you have to recondition the existing human nature and channel all the forces that flow out to converge at a single point of focus. That point can be called God, the force of creation; it can be called Guru, the energy which removes ignorance and darkness; it can be called love, Prem.