Hi all, Another little problem I've got!

Has anyone installed those beech effect wooden blinds from Argos because I've lost my instructions!

I've hung the blind up but when I pull the cords (any 3 of them) nothing moved and the blind is still in it's packaged form and won't extend.

Do I need to pull the metal clip out the first time it's used or do I need to just pull the cords harder? lol