for one group manager come prebuilt the global groups are preset groups that will house all the essentials perms all you need to do is inherit them into the worlds folder where you put the individual perm > plugins\GroupManager\worlds\world this file is like pex where you have the seperated ranks and all from there you put under inherit
g;essentials_builder or the name of the rank you want but you will have to modify it for each of the ranks you wish to have one your server
as for the not being able to build you need to set the build: true in the world group file for each world that you want them to be able to build in. On my server i have multiverse so i have to do this manually for each world and rank for that world
ex: i have a creative world and i only want one rank to build there i put build: true on that one rank and for the others i put build: false not allowing the ranks with that node not allowing them to build.
if you have more questions msg me and ill try and help you
