Kriya Yoga Concentration

[carlowillo]

In the book he mentions imagining you are looking at the third eye point from the back of your head. Do you focus on the point with your mind and imagine looking at it at the same time? I'm finding it difficult to understand/ do this. 

Is this needed? Or is it just so you keep your eyes pointing upwards. Can you just concentrate on the point normally? I can't seem to understand how to carry out the technique mentioned in the book.