http://www.dayzcommander.com/
install that and update your dayz version and make sure everything is up to date and connect to a server through the client
some people prefer http://play.withsix.com/ but either one works
make sure you have arma2 and arma2 operation arrowhead and that you have launched both games at least once individually before playing
I have Dayzcommander on now, but how do I update DayZ?
I don't even have Arma2 Operations
you need both arma 2 and operation arrowhead to play
yes or you can get it through steam which ever is easiest for you. but make sure you have launched both games once individualy before playing