Some more doc

README.md

@@ -48,7 +48,28 @@ TODO: test and continue
 
 ### Loading the map in Tiled
 
-TODO
+The sample map is in the file `map.json`.
+You can load this file in [Tiled](https://www.mapeditor.org/).
+
+Now, it's up to you to edit the map and write your own map.
+
+Some resources regarding Tiled:
+
+- [Tiled documentation](https://doc.mapeditor.org/en/stable/manual/introduction/)
+- [Tiled video tutorials](https://www.gamefromscratch.com/post/2015/10/14/Tiled-Map-Editor-Tutorial-Series.aspx)
+
+### About WorkAdventu.re maps
+
+In order to design a map that will be readable by WorkAdventure, you will have to respect some constraints.
+
+In particular, you will need to:
+
+- set a start position for the players
+- configure the "floor layer" (so that WorkAdventure can correctly display characters above the floor, but under the ceiling)
+- eventually, you can place exits that link to other maps
+
+All this is described in the [WorkAdventure documentation](https://github.com/thecodingmachine/workadventure/#designing-a-map).
+Please be sure to check it out. 
 
 ### Pushing the map