If you want to gain access to the creative server there are a few levels of building that you have to go through.
1st Level - A plot in Block City
The 1st level builder has a small plot in Block City where they can be creative and build anything they want. Anyone that builds something half-descent in here and proves they can play the game in a creative environment will gain access to Maple City.
To get a plot setup, login to the server and enter the creative world. Find an empty plot in the city and ask an admin to set you up. Type /modlist for a list of online moderators.
2nd Level - Maple City
Maple City is a free build city where you have creative access within the entire city. Building in here will allow you to have a little more freedom and also give you more space to build a bigger project.
3rd Level - City Build
You will be given a plot up to 500x300 to build an entire city. You can add your friends to the build so they will have creative in your city. The amount of land given will be determined by your plans for the city and the number of players working on it.
If you want a city build, please post a thread with screenshots of your builds in Maple City requesting it.
4th Level - Full Creative
Full creative players will gain the ability to use the /gamemode command to switch to creative anywhere in the world. This is given to players that demonstrate the ability to build great bulidings and also players that are good citizens on the server in genereal. This is something that is given to players and not something that you ask for.