Andis pet clipper kit

Question

I have just purchased a pet clipper kit, I am not able to attach the things that look like combs. i am assuming these are clippers. please help i can only get it to work on the smallest blade. i have a 16 year old standard poodle who is petrified of professional groomer so i thought i would just clip some of her very long coat myself. She is very hot with all this hair. i sincerely appreciate your help.Thanks