You probably want to use a tilemap. construct.net/en/make-games/manuals/construct-3/plugin-reference/tilemap
On trigger, for example if you click a block, change it into another block (or an empty square, in the case of digging).
To refer to the correct tile to change, for example the one under the mouse, you'll use the tilemap expressions described in the manual linked above PositionToTileX(), and PositionToTileY().
So in your set tile action, the tile x location would be Tilemap.PositionToTileX(Mouse.X) and the tile y location would be Tilemap.PositionToTileY(Mouse.Y). The tile would be whatever you want to change it to.
If the above is confusing and you're not sure how to use an expression or what an expression is, you should probably start with the first two beginner tutorials and reading the manual.
construct.net/en/tutorials/construct-3