Thanks for your answers 
I just don't understand how I can select the tile I want.
What is it that you want to do? It is hard to understand the context of "select the tile I want".
If you want to set a tile to a position for a map:
When you LOADANIM, you automatically create an ID for each tile starting at 0.
If you create your map with data, just use the ID numbers.
If you want, let´s say, a selector to hover the tiles:
Create variables for its coordinates, like SELECTX and SELECTY.
Then DRAWSPRITE 1,SELECTX,SELECTY
You can then check which tile is under the selector with:
IF TILE[SELECTX][SELECTY]=7 THEN TCHANS!
I hope it helps, but both linked examples should get you there, if you are still having trouble you need to better describe what you want.