The first six techniques are a good warm up to the more demanding final four, and each technique should be practiced for three minutes, with a break after the sixth exercise. Each exercise has been carefully thought out, and all of them help you practice the fundamental mechanics of the style - so don't think that they're too simple for you, they're essential, even for the masters!!
Take it easy
You don't have to do the exercises for 3 minutes - if you haven't got enough time, or if you're just starting out, then you can choose how long that you do them for.
In fact, if you find the exercises hard to complete, then just do them for 1 minute each - but do them every day. After a short while, you'll be able to increase the amount of time. It's better to start slow than fast, burning yourself out!
Also, remember, if you don't feel comfortable doing some of the exercises, then don't! For example, if you have bad knees or ankles, don't do the exercises with hopping. You can skip them, or just do one of the easier exercises instead. Hopefully after practicing the easier ones, your legs will become stronger, and you can start adding in the hopping exercises.