If you have managed to remove the whole cylider, look at the cylinder and you will see tab half way along it. Or you will certainly be able to see where the tab should be (by now you will have wrecked the cylinder I guess).
This tab comes out and lifts the lever and lowers it when you operate the key. What you are looking for is the lever that this tab lifts up and down.
It's easy when you have done a few, but it will all make sense when you have figured it out. The lever operates the multi locking system on every door and all of a sudden you will realise how insecure UPVC doors are.
The whole security of the door relies on the quality of the cylinder, it doesn't matter how many locking points you have.