Removing the defender: Capturing

A defender is a piece that is protecting another piece. After removing this guard, one of the enemy pieces is no longer defended. That gives you a free capture. This tactic of removing the defender is also known as undermining. When your piece is taken after capturing the defender, it is called trading.

Always look at the position. Which of the enemy pieces are the most vulnerable? Vulnerable pieces have a weak defense. By luring away or removing the defender, you can attack the piece! 

What do you have to do?
Remove defenders by capture. Then, win material.