Here is a guide for 11 miscellaneous achievements around Paradise Killer, with this one being the second one.
1. Go to the apartment area, with the two tall apartments.
2. There are blue bridges that lead north to the fields.
3. Next to the west bridge, a path leads down and to the left. There is a dog here.
4. The dog wants treats. Go towards the other bridge to the convenience store.
5. In the store, in the back left is a dog treat.
6. Give it to the dog. :)