Bring your Yoga blocks to the middle height and place them between your knees and your hips next to your thigh. Usually people tend to place them quite close to their hips, placing them closer to your knees helps to get the core squeeze that is required to lift yourself up. You can also use books or similar objects to elevate your hands. Or nothing (if you are really tough). Cross your shins. Lift yourself up and extend your legs. Now, bring your knees towards your chest and extend them again.
Butterfly with Thera Band
Bring your resistance band under tension behind your shoulders. Arms are stretched to the sides. Bring your straight arms together in front of your chest.