Hi Sue.
Peter is quite correct with his advice regarding the manual switch. In certain cercumstance the camera will focus on part of the picture that you are not interested in, that is where the manual switch comes in handy. You will also find that when trying to take a picture of a distant bird that is against a plain background, such as the sky, if the subject is rather small the camera 'hunts' backwards and forwards as it trys to find the correct focus. Again the manual focus will help. You should find the manual switch on the side of the lens, not on the camera. It is, or should be, a small slide switch marked AF/MF. At the moment it should be in the AF position.
I know what you mean about that strap, it can be a pain, I have learnt to live with it. I beleve that there are other types of strap available, some that fasten round the waiste for instance. Check round the shops when you get the chance. The trouble with the back pack, in my opinion, is that you don't have the camera ready available to use at an instants notice and therefore can miss taking that vital image.
When I tried to view that last image that you have linked to I found that it had been removed!!
Regards Roy J.