Make sure that you can get a vet appointment for vaccinations - see if you can book one now if you haven't already.
Between vaccs, take the puppy out in the car, and sit somewhere with the boot open and let him watch the world go by ('socialisation' really means 'just getting the puppy used to different things'). If you have friends with vaccinated dogs that are okay with puppies, they can come to your garden (or he to their's if they're okay like that).
Don't be afraid of making a noise around the house. I drop pan lids onto a hard floor when the puppy is a few rooms way, gradually reducing the distance and upping the noise as the puppy gets used to it (you're looking for a very quick recovery from the startle at the noise). Party poppers are also good for this - plus you can encourage play with the streamers. This is good for getting dogs used to fireworks, thunder, backfiring cars and (if you live rurally or walk them in the countryside) gas guns and gunshots.
As soon as you can get your puppy out and about, go somewhere safe and let him off the lead (or if that feels like too big a risk, use a longline and drop it). He should recall really easily - young puppies are highly unlikely to bugger off.
Teach him to settle and sleep. Be very boring when you want him to rest - put him back in his bed with minimal interaction, as often as it takes.
And play with your puppy, build the bond, lots of fuss and cuddles. Have lots of fun.