I provided images and I know they don't work for you since your device has a firewall so I'm going to provide a text answer as well. Slateport city is the city you get to after sailing with with that NPC who has a Wingull named Peeko. Not to be confused with Dewford Town, Slateport city is the one with a beach and Dewford Town is the one with the fighting gym. Once you get to Slateport City, you'll find several houses, the house you're looking for is close to the top left corner of the location and it has a faded purple roof, beige walls, and a red door.