Step One: Start by sitting in a way that doesn't block anything: sit with your legs uncrossed and with your hands resting on your legs.
Step Two: Become aware of the feeling in your toes. Wiggle them and feel the texture of your socks.
Step Three: Now move that feeling up to your legs and calves.
Step Four: Close your eyes and breathe in. Visualize air going into your body and traveling down into your legs and feet. This air is going to clean away all of the tension.
Step Five: As you breathe out, visualize all of your tension as a dark cloud that that you just blow out into the air.