If you build your own, I recommend making it low to start with - maybe only a couple of feet off the ground. You will need some thin wood if you make your own, at least for the place where the ramp meets the ground. Otherwise your wheels will catch, unless you have huge wheels. A lot of skate parks will have small ramps like this, or a section of ramp that isn't too high that you can try this on. Look around, or get some help building a ramp at your house.
Ride straight at the ramp or transition, getting up a good amount of speed. You are going to want to be going fast enough to clear the edge or coping of the ramp. And, the faster you are going, the higher your ollie will end up being. For your first ollie, start small - just get enough speed to clear the edge of the ramp. Later, when you are better, you can try and launch yourself higher!
