Orange can now import Tiled map files.  If the editor isn't working for you (or if you prefer Tiled), you can make your maps in that -- just use an existing tileset from the Orange archive or add a new tileset (make sure you scale it 2x without any interpolation if you do so).

Before you save your map files in tiled, go to Edit -> Preferences and change "Store tile layer data as" to XML, or I won't be able to import the maps correctly. :)

A quick note on map layers.  Orange assumes you have a single layer that's meant for map collisions.  On that layer, any non-zero tile is considered solid.  Tiles on that layer and the layers below it are drawn below the player, and tiles above that layer are drawn above the player.