well VIP is where you donate real money to the server.
Supporter is when you've donated to the server but your VIP has run out.
Veteran can't be obtained at this time, unless you have tokens (which were given out at the end of V5 during various events and as incentive for those to continue playing on the server) where you can buy veteran.
Prefect, you can apply here:
http://www.noobscraft.com/general/prefect-application-(moderator-application)/Mod can only be obtained once you've gone through the prefect rank.
and Admin, nobody can get admin. haha
I hope this answers your question.