How do I make notes and keys that can unlock doors?

[Codex]

Hey people!

I just wanna know, how do I make notes?
I wanna write something like; "A key is hidden somewhere - find it, unlock the door and escape the room!"
So the player knows what his objective is.

Another thing; I just found out howto lock doors, but how do I make a key, that unlocks that specific door? In "Items" there are differnt keys, but none of them works.

Any help please? I'm new

[Khyrpa]

these might prove useful:
http://www.youtube.com/watch?v=ABI7NUqkX...ata_player
http://www.youtube.com/watch?v=uGCTwQQSZ0A