Read up first of course, lots of good source material here. Then get in touch with the local folks running the game. Make sure you'll have all the gear you need like proper eyewear and the like. Then at the game ID yourself as new and see if there is a player or group that will take you under their wing hands on.
Some places will have a bleed out rule where you like on the ground when you're hit, others will have medics, and so on. That makes it hard to guess what the flat out rules will be here in this thread.
Airsoft, where nothing is hurt but feelings.