Find an elevated bench (or take a flat bench and raise it by placing a block or platform underneath one end). If neither is accessible, a flat bench will suffice.
Select the appropriate dumbbell weight and rest it on the ground at the lower end of the bench.
Lay down on the bench face down and situate yourself to where your knees meet the edge of the bench.
Take the dumbbell from the floor up in between the arches of your feet (or have someone place the weight in between your feet for you).
To finalize starting position, your legs should be fully lengthened and your arms hugging the bench for support.
Initiate the movement by curling the weight up towards your butt via flexion of the knees only. Raise the weight as far as you can or to a 90 degree angle ideally.
After a pause, lower the weight back down slowly.
Repeat for however many reps you need.
Dumbbell Hamstring Curl Tips
Avoid using too heavy of a dumbbell to avoid swinging motions of your body. Your body should remain fixed throughout the set.
Focus on pulling the dumbbell up by engaging your hamstrings.