Best advice I can give you is to relax and enjoy him mintchoc. So many people try too hard to do everything perfectly and find it takes a lot of the fun/joy out of having a pup.
Basically all you need to do is:
1.) Decide on your house rules (eg is he going to be allowed upstairs, on furniture etc) and be consistent from the off.
2.) Carry him out and about as much as you can to expose him to the world and reward him for being calm and/or reacting appropriate to new and novel sights, sounds and smells. Then get him to puppy classes as soon as he's had all his jabs.
3.) Make training part of every day life and make it fun. So for example, sit and wait and come can all be part of meal times, down can be incorporated into playing with a favourite toy etc. Lots of very short sessions are the way to go, you don't need to do great big complicated, planned training sessions at this age.
4.) Distraction, redirection and reward are a million times better than telling off or any other form of negative intervention and actually help build and reinforce your bond with your pup, rather than damaging it like punitive methods do.
Sometimes it can seem like such a huge, scary thing, especially if you're trying to follow puppy books to the letter. (Something akin to trying to follow one of the myriad of baby books there are on the market and finding you have no time to have a life around the routine, iykwim.) It doesn't have to be like that though.