You don't need to do any wheel building yourself. You can buy the hub motor pre-installed in a wheel. Simply purchase the proper diameter wheel for your frame. The only aspect to keep in mind is to get the right sized motor for your frame. Too many people chase the "big number" hub motor wheel, picking up a 3KW or 5KW motor, and installing it on a frame that will shake itself apart, or a frame that isn't made to travel at 40MPH/60KMH with brakes incapable of handling that speed. If you do end up purchasing just a hub motor, and want to fit it to your current wheel, find a good bike shop that does wheel rebuilds, and have them put the motor in for you and tension the spokes. Takes like an hour of their time. My old motor is 500watt, which gets me a top speed of around 18MPH/30KPH on the flat and a 15 mile range. I am contemplating going to a 1KW motor. Eventually. Maybe.