The word .. ‘ Anapanasati ’.. in Pali language means .. to direct one's total attention and awareness only on one's normal, natural breathing process. 

‘ ana '    means    ‘ in-breath ’
‘ apana ’    means     ‘ out-breath ’
‘ sati ’    means    ‘ be-one-with ’

In ‘ Anapanasati ’, attention of the mind should constantly be on the normal, natural breath. The task on hand is effortful, joyful oneness with the breath.
No ‘ mantra ’ is to be chanted .. no form of any ‘ deity ’ is to be entertained in the mind .. no hathayogic pranayama practices like ‘ kumbhaka ’ .. holding the breath .. should be attempted.

Any comfortable sitting posture can be taken. The posture should be as comfortable as possible. Hands should be clasped and all finger should go into all fingers. Eyes should be closed.
The crux of the matter is to resist, to the best of our abilities, the routine wanderings of the mind. All STRAY THOUGHTS SHOULD BE CUT right away, as and when they keep arising.

“ When we are with the breath-energy, the mind becomes rather empty. Then, there is a tremendous in-flow of cosmic energy into the physical body. Gradually, the hitherto dormant third-eye begin to become activated. And, by and by, cosmic consciousness get to be experienced. ”