You can get Level 2 whenever you want. Even before Level 1.
To get more benefit from Level 2, however, you will want to at the very least go through Level 1.
While doing Level 2, keep doing the Active Exercise and Sitting Meditations from Level 1. Do Level 1 during one session and Level 2 during another.
When you have seen improvement in your physical condition and when you can feel the energy, then you can give up the Level 1 Active Exercise and just do the Level 2 Active Exercise.
The Sitting Meditation is good for both levels, especially the Small Universe.