What are the simplest somatic practices I can do alone to calm my nervous system?

Start where you are. You don't need special knowledge or a teacher watching over your shoulder. The body responds to simple, repeated signals that it's safe. First: feet. Press your feet into the ground and feel the solid earth beneath you. This sounds almost too simple, but your nervous system recognizes ground. It's ancient. Do this for a minute when you wake, when you're stressed, whenever you remember. Second: breath. Not fancy breathing techniques—just longer exhales than inhales. Breathe in for four, out for six. Your exhale activates the parasympathetic system, the part that says "you can rest now." Five minutes changes everything. Third: slow movement. Walking, gentle stretching, swaying. Not exercise—just conscious movement where you notice what your body feels like moving through space. This tells your nervous system you're not frozen, you're capable. Fourth: hand on heart. When you're overwhelmed, place your hand on your chest. Feel your heartbeat. This is self-soothing at its most primal. Animals do this naturally. Do one of these for two minutes daily. Not because you should, but because you're learning to trust your own body again. That trust is the foundation of everything else.