Start standing with one foot on the bench behind you, lower into a lunge, let the weights come down close to your shin/ankle & slowly stand back up. Lean your chest slightly forward throughout the movement & make sure you're not arching your back!

Beginner: bodyweight -7lb dumbbells

Intermediate: 10-15lb dumbbells

Advanced: 20-35+lb dumbbells

*Modification: do these without weight or just regular lunges on the floor.