Stand up:

Before you are ready to stand, make sure that the chair or bed is stable and firm. Normal legs are supported on the ground and the body moves forward to the edge of a chair or bed. Put the two crutches together, hold the handle of the crutch with the hand on one side of the affected leg, and hold the armrest of the chair or the edge of the bed with the hand on the other side. Hold your hands together, while your normal legs stand up and keep your feet steady.

Note: Before you start walking, make sure you're on your feet, and then separate your crutches on both sides of your body.

Sit down:

Slowly retreat until the normal leg touches the edge of the chair or bed. Keep your weight on your normal legs and fold your twists together. Hold the crutch handle with the hand on one side of the affected leg, put the hand on the chair or the edge of the bed on the healthy side, then bend the knee on the healthy side and sit down slowly. Take your time sitting down and always keep your arms next to your chair.

Note: Unless the doctor allows the affected leg to bear some weight, the sitting down process still needs to keep the affected leg from leaving the ground.