I clip Millie short as otherwise she takes so long to dry. I clip across the top of her head, back of neck, back, inside of ears and front of legs as short as I can (no guard on the clippers). Her ears, chest, belly and back of legs I clip to about 1-2 inches (No. 1 or No. 2 guard on clippers). I blend it in so there isn't any obvious differences. Her tail I clip the top short and leave feathers on the bottom. Charlie I do similarly but leave feathers and belly slightly longer and don't clip down the front of legs, I'm also more careful with the blending and use thinning scissors for some of it. When he's just been clipped you can see all the black spots on his back which my Mum loves
. I would take Ollie to a groomer first so you have an idea of what to do. Also his coat will be a lot easier to manage once he's lost the puppy fluff. Also if you're clipping him to keep him clean then you would be better to keep it short in the winter as well and use a coat/equefleece.
Sorry I haven't got any photos that really show you what I mean!