When it comes to Minecraft permissions there are literally more than a dozen alternatives you can use. In our professional experiences we have found that GroupManager is the best bet for ease of use and stability within McMyAdmin.
Make sure GroupManager is Installed:
If you are using Essentials you should not need to install anything else. If you see issues later in this guide with permissions not working go to the game panel under "Game Mods" and install "GroupManager".
Set Permission Exporting:
In McMyAdmin go to "Configuration => Features" and make sure that Permission Exporting is set to GroupManager.
Create your Default Group:
Go to "Users and Groups" in McMyAdmin and select a premade group or create a new one for your normal players. In the playername area add "*" which means "anything not listed elsewhere" then set the group to default.
Create your Owner/Admin Group(s):
Create or use a premade group and set your name as well as any administrators you plan to have access to the players list. From here add the following permission nodes to allow full access to all commands:
worldguard.* (if installed)
worldedit.* (if installed)
lb.* (logblock: if installed)
You and your fellow administrators will not be able to use all commands.
That's basically all there is to it!