Anti-theft light on and will not start

The steering column went bad and I had to change it and went with a used one. Went to start it and when I turn the key on turning over the theft light came on now the car won't start. The lights will come on on the dash but the starter won't crank. Now the Anti-Theft lock symbol on the dash is on. What do I need to do to get it going again? Also I don't have the original column and key. I know that was probably stupid of me. But how do I get it running.my youngest daughter just turned 18 and she's the one going to be driving it that's why I need to get it going. Can you help me please? Need some professional advice.