The process can be broken down into these 4 steps:
Step 1. Close the choke, then open it to about 10% open.
Step 2. Hold the clutch down and get some speed by using the pedals.
Step 3. Gradually let go of the clutch, while simultaneously giving it gas. This doesn't have to be fast.
Step 4. Let the engine warm up for about 2 min then open up the choke to about 75% open. You can do this while riding or you can get off the bike to do this. When you open the choke, you'll notice a drastic increase in throttle power.
Please watch this video for guidance: How to Start a 2-Stroke Motorized Bicycle