signs

Place the sign on your overworld. Directly in front of it place a direct warp combo type. Create another screen identical to this one. On the duplicate screen have a guy, thats invisible, and the message you want to appear. Create the direct warp combos around the sign. Replace the one in front with a normal walkable combo type.

Set the warp from the orignal screen with the sign to warp to this duplicate with the message. Use an insta-warp type. Then set the warp from the screen with the message back to the original screen.

Test it.

Don't forget to have a separate DMap for the screen with the message with a level number higher than 0.

And Direct warp is a combo type.

Readable signs are on the list of future plans, so maybe it'll actually be implemented into the game. Who knows?