Did the instructions tell you how to start the engine? Usually put it on choke, pump the primer 8-10 times, fully squeeze the throttle then pull until it sounds like it's about to start. Put it on run and then fully squeeze the throttle and crank until it starts, then you can let it warm up
Why are you setting the posts before driving them in? I'm pretty sure you're supposed to set the driver on the top of the post when the post is at something like a 45 degree angle from the ground and then stand it up so you don't have to keep free lifting the driver up over your head.