Response:

When you are using a breath-based meditation, then you lightly bring your attention back to your breath whenever you realize that your mind has drifted on to other thoughts. 

There are also some meditations where you bring your attention back to your silent witness awareness when you notice your mind has wandered. 

It’s not a matter of which one you should focus on, it’s a matter of which meditation you are doing.

Love,

Deepak