How to fix project not opening

ok, i was simply trying to make tilemaps for kristal. the tutorial told me to delete the old tilemap and other thing (idk what its called but its like the actual map). it was not letting me so i went to the files and deleted it. now it wont let me open the project… idk if this is a bug or just a skill issue idk

It’s unclear from your description what you did, and if you’re talking about a project you made or one you downloaded. Could you link to the tutorial you’re following? Maybe that’ll clear things up.

What was the file extension of the file(s?) you deleted?
Does Tiled show anything in the Issues panel or as a pop-up when you try to open the project? How are you trying to open this project?

And a bit of vocabulary: In Tiled, there are Tilesets, where your tiles come from, and Tile Maps, which are the maps/levels/rooms you build from those tiles. It sounds like you might be referring to tilesets as “tilemap”, which is confusing in this context.