RE: GEE BEE 751
I tried to look up the model supplier and came up with a few, however, none had a manual that was down-loadable, so it's difficult to answer the question without having one in front of me.
The problems you could be encountering is not having the motor hooked up correctly to the ESC. In the model specs, they show that it's a brushed motor design so there are only two wires going from the ESC to the motor.. and of course, two wires leading from the battery to the ESC, excluding the wire harness for the throttle.
So, you must have the battery connected to the ESC, then the throttle from the ESC to the radio receiver, and of course, the wires from the ESC to the motor. That combination should be checked and make sure it's correct.
One quick question, though. Is the intended "pilot" experience in RC flight? If not, this is a very poor choice for a beginner level RC aircraft. These are not very forgiving as a good high-wing trainer would be.
CGr.