Press wasd to move the "cursor" around, space to place a tile, left and right arrow keys to switch tiles. Press 2 to move the cursor back to the beginning if if goes out of alignment, and r to rotate a tile (not recommended with the sample tiles) To upload your own tilesets, go to the sprite "import" upload a gift version of your tileset that is 128x128 and delete the first sprite image and the sprite "sample"
sample textures by me I made this because I couldn't find a good way to easily test a tileset so here you go
