I used to be confused by that too! Once you've placed the line blaster you should see at the top of the game board a green and red tick which will confirm or cancel your placement of the line blaster once you click on either one!
I used to be confused by that too! Once you've placed the line blaster you should see at the top of the game board a green and red tick which will confirm or cancel your placement of the line blaster once you click on either one!