How can I program my Audi A4 smart key?

I recently bought an Audi A4 and I want to program the smart key to unlock and start the car. Can anyone provide a step-by-step guide on how to do this?

To program your Audi A4 smart key, you will need to insert the key in the ignition and turn it to the 'on' position. Then, press and hold the 'unlock' button on the key for five seconds. Release the button and turn the key off. Repeat this process for each key you want to program.

You can also program your smart key using the key fob itself. Put the key in the ignition and turn it to the 'on' position, then press the lock button on the key fob and hold it for five seconds. Release the button and turn the key off. Repeat this process for each key you want to program.