What are the steps for programming additional keys with two existing keys?

With a first and second original programmed key in the ignition, follow these steps: turn on the vehicle, turn off and remove the key. Within five seconds, insert the second original already programmed key and turn it on then off again. Finally, within five seconds of turning off the engine with the second key inserted, put the new key to be programmed into the ignition and turn it on. The security light will turn off once programmed.