Although Breathing is important to your practice, in Level 1 it is more important that you breathe slowly and evenly than it is to do Qigong breathing.
There is no need to rush into reverse breathing at this point. as remedios mentioned above, the healing happens with the aid of your mind, movements, attitude, visualization, and simply slowing down your breath.
When you get to the point that you want to play with reverse breathing, do it for the first three breaths at the beginning of your exercises or sitting meditation, then go back to your regular breathing. Continue doing it this way each time you practice, and like the tongue at the roof of your mouth, bend at your elbows, smile on your face, etc. it will all be carried over naturally into your practice without you even realizing it.
Bouncing for a couple minutes before for your exercises with your arms above your head and hands dangling, as well as the Harvesting of Qi cupping exercises throughout the day can open the breathing system channels.