Stand with your feet a little wider than shoulder-width apart with your toes pointed slightly out. Hold one dumbbell vertically at chest level with both hands.
Keeping your core engaged, push your hips back, bend your knees, and lower your body into a squat until your thighs are parallel to the floor (or as low as is comfortable for you).
Press into both feet to straighten your legs and return to the starting position. That's one rep.