Puppy has been trained to pee on balcony, how do we train him to pee outside?

Hi all,

We’ve trained our 13 week old puppy to pee on a patch of grass on our balcony. Now, he’s vaccinated, we want him to pee outside. We take him out after meals and naps, become very boring and stand in the same bit of grass we want him to pee on. Unfortunately he’s not relieved himself there yet. Any advice on how to let him know it’s okay to go outside?

Any suggestions?

Thanks!