First, you will continue repeating the word for most of the time your eyes are closed. Another typical occurrence is that soon after you begin repeating your mantra, your mind begins to wander. The third thing that may happen is that you may fall asleep. Whatever happens during meditation is appropriate as long as you have the single intention of repeating the mantra and returning to it when you wander off. Whenever it occurs to you to do so, simply insert the mantra in under all of your other thoughts that come and go. This is your only intention.