Hi Lex, when you buy a new Aviator Harness, which this one is, they come with a DVD showing you how to fit it. It is fairly easy to fit, a little bit fiddley until you get used to it, but it's fine. Before you try any harness I would say your bird needs to be comfortable with you handling her wings, she needs to be used to the harness lying about for a while, let her touch it and play with it, associate it with treats and nice things. Practice with it just laying loosely over her back before you try to put it on her and make sure she is ok with that first. There are many threads on here that will help you, and YouTube has some tutorials on harness training too. It won't happen overnight, but is well worth perservering with as it's just great being able to go for a walk with your grey. Alfie really enjoys coming out with us - at least she seems to!