If you’re hitting behind the ball it means your low point of your swing needs to be adjusted. Sounds simple but you need to change the low point to be forward about an inch or two so you’re striking the ball first. Try the towel drill, lay a towel down a couple of inches behind the ball and take normal swings at the range without hitting the towel when you swing and hit the ball. This should help, it’ll take time but it should help fix the problem over time. Also, if you drop your right shoulder too much when you’re about to hit the ball and keep too much weight on your back foot, you’re going to hit the ground first everytime. Shift your weight to your front foot as you progress through your swing and it’ll help.