Hi - lovely pup!
Would suggest obviously keeping him cordoned off with paper down - if he pees anywhere but the paper, lay the paper over the puddle so it soaks it up.
If the paper is not too saturated, when you let him lose for playtime etc, put the paper where you want him to go, then again when you let him out, take the paper and pay it utside - its all about the scent really, and when he gets it right - loads of praise and maybe a little treat - when he gets it wrong, say NO and place him on the paper.
Always clear up accidents straight away to avoid him going in the same place - so the only place he can smell his pee is on the paper - then gradually start letting him outside to go - once he is going in one place all the time you can make the area of paper smaller, eventually dispensing with it altogether.
Letting him go on a grassy area is a good idea because he will then do this when your out for your walkies !
This process can take from 3 weeks to a couple of months, depending on your pup.