There are multiple ways to accomplish this and everyone has their own method.
I can tell you what has worked for me with several different dogs. I am a firm believer in crate training! And one year old is not to old to start! I trained Angel both indoors and out. The way I did it was, in the crate unless being supervised 100%!! Not one second out of site!! If you are not interacting with the dog with play, training, cuddling, whatever, it's in the crate! When taken out of the crate it's straight to the pee pad or outside. If successful, meaning peed or pooped, then it's party time!
I clapped my hands, smiled, praised, praised, praised! If not successful, it should be back in the crate, but, here's where you can be flexible. At this point you can keep him occupied, BUT, keep an OPEN - he will be ready to do something at this point!
The basic idea is, he should be in the crate at all times when not being "hands on" with him. And the crate should be small enough so that he can't pee in one corner and sleep in another!
Another method that works is tethering. Potty training is harder on us than on them! It is so hard to bring ourselves to confine these oh so cute cuddly little creatures! Lol. But ya gotta be strong! The short time it takes to get them trained is nothing compared to the frustration you could face for years to come!