Lots of praise when he goes outside followed by your command for it – we’re lumbered with ‘wees and poos’ 🙄
If you see him do it try and catch up and put him outside
He’ll need to go at certain times of day and after a big drink, try the positive reinforcement thing then
He’s a puppy, expect to write off many things, but gain many other things in return. I guarantee he’ll pick it up in time
Our 7 month old puppy managed to take a piss on a different floor of the house, and on our bed! He’s normally excellent other than that! (we have another dog)