[RM2K3] HOW DO I ADD COLLISION TO TILES?? (I'M AN IDIOT PLEASE HELP)

In RM2k3 you set collision by opening your Database and then selecting "Tilesets" (or "Chipsets" depending on which version you have). A list of Tilesets will appear on the left. Click on the Tileset you are using. You'll see three big buttons, labelled Terrain, Passability and Directional Pass. Click on "Passability". Next, click on the tile you want; you'll notice it'll either have an O, an X or a star. An O means the player can walk freely over it. An X means it blocks movement. A star means the tile appear 'over' the player and doesn't block movement. Just click the tile to cycle it (or right click to reverse cycle).

If you click "Directional Pass" you can change which way a player will be able to move over a tile. This is useful for cliff edges or "one way" tiles for puzzles.

Just click "Apply" or "OK" to save your changes when you're done.

edit: There is one more Passability mode in addition to O, X and Star: The Square. Only autotiles can be set to Square mode. In Square mode, the tile will block player's movement EXCEPT for the topmost tile, which will appear over the player. This is used mostly for cutaway ceilings. It's a bit hard to describe, but it's obvious once you use it.