How do you pass traverse town in kingdom hearts

Go to where you are able to go in that district. Once you have seen Goofy or Donald about three times from gong to different places. Including; Alleyway, Gizmo Shop, etc. Once you met all the places. Go back to District One and you'll have to battle Leon. You can lose or win either way it doesn't matter. Just by winning you'll get exp. Yuffie would come talk to Leon and they'll take you to the Green Room.
You'll have to talk to Leon in order to go out of the room. A Heartless would appear and everybody would jump out of the window to attack the other Heartless. Go to District Three and you'll meet up with Goofy and Donald. You'll have to defeat a big boss Heartless.

After you have defeated the Heartless, they take you to District One and they'll talk to you for a little bit. Donald would give you the magic Fire and Goofy would give you the ability Dodge Roll. Then, you beat the level. You can explore around if you want. There are some Blue Trinities on the ground so watch out for them. You can also use Fire at that door with the Fire Symbol on it in Third District.