let's say i place a building on the world map. how do i make it that the main charactor enters this building when he walks on it? and is it best to use dungeon or building editor when creating a town?

Sorry for the late reply, but here's the deal. I can't remember exactly how to go into a building in RPGM2. It's either the Warp or Teleport command. Whatever the case, you have to use the command twice. Once outside the building to move the player inside the building, and another time inside the building to move the player back outside.

As for the dungeon and building editors, they each serve a different purpose. The dungeon editor is primarily used for caves and the insides of buildings (though it could also be used for a town, though it won't look as good as making the town's outside using the map editor). The building editor is used to make the outside of a building to place in the town.