In which case you can program up to, (I think?) six keys using the 'Change the Key' function, at least I think thats what it's called?
Go to 'Change the key', it will then ask you to enter your user code. After you've done that and held the button down it will say 'Insert second key'. You take out the first key, (The dash will remain active for 20/30 seconds.) Insert the second one and turn the ignition on again. It'll then say 'Insert third key' and you keep repeating for up to five keys.
Once you have finished programming however many keys you need you just take the last one out and let the dash time itself out. After it's turned itself off leave it for a minute and then try the keys. They should all work.