It's easy to learn and practice this technique which has five components. The first step is the systematic relaxation of your physical body focusing on the muscles.
Many different sequences are useful.
Choose any one that works for you. Uncross your legs. Place your arms by your sides. Focus on the tips of the toes of your left foot. Let a wave of relaxation start there and move up over your left foot, ankle, lower leg, knee and thigh into the left hip.