Rules are simple. Two teams hiders and seekers. Hiders mission is to not be killed when time is up and seekers mission is to kill all hiders before time is up. You can hide to increase your chances to survive or just run fast. You have knife to protect yourself, syringe to heal other hiders who have been shot but not gibbed and medpacks to heal yourself. Once you are killed and gibbed you become seeker. Seeker has pistol with unlimited amount of bullets (but still needs to reload) and can respawn again if killed by hider or dead by falling/drowning etc. Any questions?
To listen voice chat is 25% of the fun. Talking is the other 75% as you can taunt seekers or talk with other hiders. If you have any chance to buy even some potato-mic (5€ microphone from regular shop) it usually does the trick if your background noise is not thunderloud.
It helps to look maps before as they are bit different from regular maps as some doors are not blocked off for example. Also practising some pistol shooting and fast jumping/running helps.
Hope to see you there.