This is the simplest part of the process leading towards enlightenment. The initial aim of meditation is to increase awareness and begin to settle the mind. When we are fully aware of something, we cannot think, and this is the state we are trying to develop in this phase.
There are two basic techniques which should be employed here:
1. Meditate on breath.
2. Promote awareness by focusing on objects.
These two techniques must be used in tandem, but we must be relaxed during this process. If we forget about breath, or to remain aware of our surroundings, don't be concerned. All we can do is practice these things when we remember to.
How to breathe:
Breathe into the belly instead of into the upper chest. Aim for the point about an inch and a half below the belly button and focus the breath on this point. The belly should expand when we inhale and deflate when we exhale. The chest should be completely motionless during this type of breathing.
Now we know how to breathe, we practice it whenever we remember to and simply be aware of the breath by watching it go in and out, and feeling our belly expand and contract. By watching the breath like this, the mind begins to calm.
To develop awareness is a simple matter indeed. In the course of everyday activities, we try to notice things which we normally haven't noticed before. For example, on a regular walk or run, look at the roofs of houses, and the distant trees, and specific details of things that would normally pass by without a glance. We will find our awareness expands markedly, and will wonder how we missed all these details which we are now aware of.
We practice this when we remember also, and over time begin to spend more and more time in aware states breathing into the belly.
These techniques will naturally evolve into more complex practices so there is really no timeframe which needs to be considered as this process will actually come to an end of its own accord.