If I remember rightly to when Max was a pup a fortnght after his second injections at about 12 weeks. I know you'll want to show him off but don't forget only short walks at first and gradually build up he's only a baby.
Callie had her first jab at 8 weeks, second one at ten weeks, then we had to wait a week before taking her out, so I think about 3 weeks after the first one........
Technically a week after the second jab, but you can carry them round places provided you don't put them down where lots of dogs go, like the local park. I take mine out to a disused airfield for a short wander round. Gets them used to travelling too. More dogs are put down because of lack of socialisation than ever die from catching something.