One of the questions bothering novice potty trainers is, "what if the doggy doesn't go when he is brought outside?"
At first, I used to wait for them. So it doesn't matter if I have to stand for 30 minutes in one spot, as long as he eventually goes potty. This would do for the first couple of days (where you still have the patience), but the problem is that we are but humans with finite tolerance. Meaning, the 30 minutes spent outside or at the backyard being bitten by mosquitoes or frozen by the cold night isn't exactly a good experience worth repeating.
After having to bring 3 dogs outside everyday to go potty, it becomes tiring especially when they get distracted- forgetting their purpose of being walked. Although some have already adapted to the system of walking = potty, others would rather roam around. So to deal with this, the best thing to do is come back and let him out again after 20 to 30 minutes later.
Still not potty-ing? Wait for 5 minutes and bring them back to their crates. Add another 20-30 minutes before taking them out again. It will take some time for your doggies to fully adjust to the schedule, but consistency is the key to a happily potty trained puppy.
Don't forget to give your doggy praise (or croon positive reinforcement) for him to remember he did this particular activity right.