The only way to join the Vanilla (and AMP server) is to become part of the V.I.P. group. The only way to do that is to get elected by other current V.I.P. members. If they like you, they can nominate you and vote for you. We do this no more than once per month.

The reason for the V.I.P. group is to have a bunch of people we like to play with. This means if they will only elect and vote for people that they actually like. So if you wish to become a V.I.P. member then get to know other V.I.P. players and get noticed in a positive way. Also, be patient. You won't get elected over night, people will have to get to know you first.