how to make puppy pee outside in the garden?

[x89]

So, I recently moved and i have a small garden/ fenced in area where he can play. my puppy is 1 year old & he did marked his territory when we first got here but after that, he would jump at the gate to go outside to the vast areas of trees and grass to pee on a leash. he does poop in the garden though. so how can I make him pee in the garden by himself instead of taking him out all the time?

I do take him on walks every morning and night, but i cant take him during the day because i have school and such.

Thanks!