Arrow keys to move on screen. WASD changes an overall coordinate, but it's not used for anything. Press Z to begin choosing a clone. Up and down to scroll through tile costumes. Press X to place down tile.
Relevant code for placing clones located in the top right of Tile and most of Cursor. Tiles say their unique index number, which doesn't seem to always work. Bugs: Changing costume changes all previous costumes(?) Each previously placed tile gets duplicated and its costume may be changed and place by the new tile position(?) I shared this because either Scratch behaved extremely strange or I don't understand coding.