5

Find five candidate moves. Go down the branch of just one of them. This is what it means to calculate three moves ahead. You don't just pick one move and follow it. You pick as many as you can, and then analyze each one, finding the best possible moves for your opponent as you can, and seeing if you have a good response to it. There is a rule among strong chess players that says "Look at all checks and captures." There is a move here that satisfies both. Look for a moment at the board and see if you can figure out what it is, and then go on to the next step. But first look for it.