You can view a good description in the comments in your Towny/settings/config.yml file for most of the permissions. This page is more to show what you can do with them.
Here we have the default group containing the important
towny.nation.* permissions. Without those, a player cannot even become a resident to a town (
Next up is the admins who get all the permissions. They get the very important ‘towny.admin’ node which pretty much lets them do anything. You also set the ‘town_maxplots: -1′ so that they arn’t limited to the amount of plots they can own. Actually it’s the global number set in config.yml, but if that’s -1 as well, then it’s infinite.
Now your moderators might not be trustworthy enough with full access, so you’ll assign them the ability to travel to other town spawn points, and let them fix silly mistakes in the wild.
By default, Towny prevents players from building in the wild. You can change that in the config, but if you might like to keep it like that and assign individual groups as jobs. Below is a sketchup for a Lumberjack and Engineer. The former can destroy wood and leaves, and place the saplings to replant that forest. You might also want to give him a ladder block so he can reach the tree top. The second is the engineer, who can build railways between the cities.
groups: Default: default: true permissions: - general.spawn - towny.town.* - towny.nation.* - towny.spawntp inheritance:  info: prefix: '' towny_maxplots: 1 build: true suffix: '' Admins: default: false permissions: - '*' inheritance: - moderator info: prefix: '' towny_maxplots: -1 build: true suffix: '' Moderator: default: false permissions: - general.time - general.teleport - general.teleport.here - general.player-info - towny.publicspawntp - towny.wild.* inheritance: - default info: prefix: '' towny_maxplots: 3 build: true suffix: '' Lumberjack: default: false permissions: - towny.wild.block.6.build - towny.wild.block.17.destroy - towny.wild.block.18.destroy Engineer: default: false permissions: - towny.wild.block.66.* - towny.wild.block.27.* - towny.wild.block.28.* inheritance: - default