hi, i would like to know How i could check if someone was a guest and if so they receive a message every 3 minutes
You need to be more specific, what do you deem a "guest". How are you currently keeping track of who isn't a "guest". Etc. If you're a little more specific this would probably be very easy to implement.
well i use prefixer im wondering if i could find out if the personm have guest in their title and if so send them a message every 3 minutes
I took a quick look to prefixer src, The way you could do this is by getting the properties file that prefixer uses to store players prefixes and with a bukkitschedule, every 3 minutes check for guests and send them a msg.