96 cavalier engine swap problem

i just replaced my engine and got the new one in, and got everything plugged in, and when i turn the key nothing happens, and i have a theft light on the dash now. i jumped the starter with the key in run, and the engine started right up, i turned it off and tried the key again and nothing. the engine came from a 96 sunfire. anyone have any suggestions or idea what to do to get the theft light off and to get the ignition working?

turn your key to the on Position but do not start the vehicle. Your theft light should be on. leave your key in the on position without starting for 20 minutes. Your theft light should then be off after then. Now turn your key to the off position but do not take your key out of the ignition. You can proceed to start the vehicle and it should run