If your just getting started with Yoga the the thing is to keep it real simple and just work on stretching and basic movements.
When you have mastered these then move on to more advanced Yoga strength positions and develop core, upper body and leg strength. This will enable you to go on to more difficult exercises and Yoga positions.
The Yoga block is the perfect tool to help you get started (along with a Yoga exercise matt).
Check out Yoga Block HERE