Lock / Key - not working ... I must be doing it wrong

Having trouble with the LOCK / Key thing...
Made a New Lock & Bolt
Made a Key
Took the Key and Clicked it on the Lock & Bolt, it did the numbers thing.
Took the Lock & Bolt and applied it on Gate, it did the numbers thing..
Gate doesnt want to open, right clicking on it, holding key doesnt do it, having keyring .. nothing works.
Made a New Lock & Bolt
Made a Key
Took the Key and Clicked it on the Lock & Bolt, it did the numbers thing.
Took the Lock & Bolt and applied it on Gate, it did the numbers thing..
Gate doesnt want to open, right clicking on it, holding key doesnt do it, having keyring .. nothing works.