Why wont it start after replacing steering column

You have a concern with the immobilizer anti-theft system. Something from the old column that is needed has not been swapped to the new one. It may be that it's not possible; it may be that programming will be needed for any and all keys. It could be that fuses are blown. Hands on inspection and testing with proper diagnostic and programming equipment is needed. www.repairpal.com/repair-shops