Hello! I started my Hatha Yoga practice about 10 days ago. At the end of all positions, we are asked to relax and meditate on energy for 5 minutes. I don't know what that means, can someone explain to me? I, in particular, put my focus on the whole body, part by part, try to feel the energy and then imagine myself covered by a bright blue light (which would be the energy) is that correct?

I think that really just means: relax and feel.
Maybe I'm wrong. I suck at void

You can imagine your aura and your light body or just your aura and try to feel it because it is amplified during that time from the hatha yoga.

Like this
https://www.satanisgod.org/www.angelfire.com/empire/serpentis666/Human_Soul.html

You can also do affirmations during that time, positive ones for protection or whatever goal you want to focus on. Just make sure you dont start that during a void moon