It is absolutely normal to experience some challenges when practicing meditation. Your mind will wander and you will be unable to focus; this happens to everyone.
The mind is as hard to master as the wind claims Arjuna in the Bhagavad Gita (the sacred Hindu text). There are, however, some great ways to make it easier.
There are different kinds of meditation and people often want to know what they are actually supposed to do when they meditate. Concentrative meditation is one such way.
Contemplation is not thinking, interpreting or evaluation; it is an awareness or perception and a non judgemental quality of mind. It is a popular way to meditate.
Witnessing is a simple and powerful meditation technique. It is effective in improving mental peace in general, but its essence has to be understood, before one starts to practice it.