Door Handle Nightmare

[ppitcher]

Hello
I am mechanically crap. But I thought I had broken my door handle, so i purchased a new one and have spent the last 1 hour fitting it to find it doesnt open the door. It is the correct door handle but to put it in quite a basic way, i think the little hooky thing which is supposed to release the catch to open the door is not there? is that called an inner catch or something....
The inner handle works, but this new handle does not open the door.

Please - anybody, please help me - im losing the will to live.

Phil