How old is the lab?
I would say a lot of short walks would be best at this point. Go as many times as you can around a 2-3 blocks. The first time you go you might not even get to the end of one block. It takes a bit to get use to some catch on easier than others. Let the dog judge how far you go, but for now I wouldn't go too much further than 3 blocks and then you can come home and go back out in 10 mins if you wanted.
I would say a lot of short walks would be best at this point. Go as many times as you can around a 2-3 blocks. The first time you go you might not even get to the end of one block. It takes a bit to get use to some catch on easier than others. Let the dog judge how far you go, but for now I wouldn't go too much further than 3 blocks and then you can come home and go back out in 10 mins if you wanted.