This is very simple and basic exercise. Have a 15 minute soak in a tub. Alone. For some, this may be a challenge, for some it may be a pleasure.
If you are attempting self care, start where you can, but start.
Make this as simple or elaborate as you would like. You can add scented oils, candles, glass of wine, bubbles etc. Or you can draw a bath and soak. If you do not have a bath, have a long 15 minute shower.