Question about Potty training 6month old pug who was litter box trained

We recently got our pug puppy a little under 2 months ago. He started out litter box trained from the breeder, but we only did that for the first 2 weeks as he was getting acclimated to his new home. He is 6 months old, and when we take him out, we ring the bells and take him outside. He knows exactly where to go when he is outside, and once he is done goes right back to his exercise pen(that we shrunk down already because he was peeing in the corner away from his crate)

,
He can hold it all night(about 8 hours), but when he is outside of his crate/in his play pen during the day he will just go to the bathroom. He is a super energetic dog(especially for a pug) so he will ring the bells, and I will not know if he wants to play or needs to go to the bathroom. When I am working on my computer, I will look over and he will just be peeing, and I do not feel like he is giving any signs that I can tell

my questions:

1. All the posts I feel like are dogs that are 3-4 months old. Im probably being crazy, but all hope is not lost because he is 6 month old, right?

2. What are the steps to take to have him associate outside with the place to go to the bathroom?

3. Since he has been peeing there, do I need to remove the pee smell/enzyme somehow so he stops going in the same place?

Thanks in advance for the help!