Facebook help!!! joining high school networks??

ok so i cant figure out how to join my high school's network. like i have a lot of friends in the network, so i know how to get to the network page, i just can't JOIN. like there's no place that says "join network" or anything. HOW DO YOU JOIN ONCE YOU ARE AT THE PAGE...ya thats pretty much my question. lol. thnx guyz n i'll luv u forever if u answer this for me :) (o btw, some ppl have said if u add someone from the network as ur friend u somehow r added to the network...not the case!! and also i dont have a high school email address. ok thnx mucho guyz!