sex for the first time

hi I haven't had sex before but will do soon. my partner has had multiple partners before. I am just really anxious about how to do it right? especially immediately after, what am I supposed to do? lie there? go to the bathroom? do I put my clothes back on? if I bleed will I need a sanitary pad? what do I do if I bleed? I just have no idea and don't want to make a fool of myself. thankyou for any replies!