The golf swing is a sequence. If the sequence is out of order, the swing won’t be executed properly. One of the main causes of hitting behind the ball is starting your downswing with your arms and the club, instead of your hips and weight shift. The club bottoms out where your sternum is, so we want the sternum in front of the ball.
A drill you can do is to balance on your lead foot with your toe of the trail foot down for balance (heel up). Hitting half shots in that position will ensure your sternum is in front of the ball and weight is in the lead foot at impact. I also like to put a visual aid in front of the ball about two inches (ex. Leaf, ball mark, coin, tee) and swing through the ball hitting the object.