Custom maps?

Hi, I'm kind of new to the whole pserver side of town but I currently love a server I'm playing on, and the founder asked if I would be able to create some custom maps for him (Like a new nexus and stuff) but I cant seem to find a tutorial anywhere on how I would go about doing this. I would appreciate any kind feedback on this issue. Thanks

First of all he needs to give you a rank for you to be able to use "Editor" on his client, you can also make your own server and do it there. Once ur in the editor you can make as many maps as you want