my friends tell me they have masturbated i don't know how to

Hi, the best way to start masturbating is to learn about your body and where it feels good to touch and not just your vagina area.
Start by relaxing and laying on your bed naked then just run your hands softly all over your body paying special attention to your breasts and nipples and your find your nipples should harden to touch.
Also I would take a mirror and flash light sit on the floor with your legs apart and explore your vagina, see how you get on and if you want more help just ask :-)