1) To start lay flat on your back with your knees bent. You want your heels to be as close to your glutes.
To add weight use either a dumbbell or a weighted plate and place it on your pelvis and hold it with your hands. Once you reach the top
2) Exhale and push your hips up. Push as high as you can. Keep your core tight throughout this movement. When you are at the top of the movement, your back needs to be straight and not arched.
Flex/squeeze your glutes as you're pushing up. Once at the top of the movement hold it for a second while squeezing your glutes.
3) Inhale and slowly lower your hips back to the starting position.