I don't see why people require you to pay them to do this?
Personally i suggest group manager which is a plugin compatible with essentials. You create the groups in the groupmanager file (plugins > groupmanager > worlds > [world name] > groups.yml), there are examples of what your group should look like inside that file.
Almost every plugin has a list of permissions that can be found on the internet on or the plugins webpage, this is the string you will copy into the list bellow the "permissions:" section in the groupmanager file.
To add ranks (my way) you go into essentials and scroll down till you see essentials chat. Near the bottom of that section it will give you a exemplar that looks like this

group-formats:
# Default: '{WORLDNAME} {DISPLAYNAME}&7:&f {MESSAGE}'
# Admins: '{WORLDNAME} &c[{GROUP}]&f {DISPLAYNAME}&7:&c {MESSAGE}'

You will want to create your own string for each group using color codes (&c,&f,&7 etc) to color each section of the rank, this is an example of a Moderator Rank.
Moderator: '{WORLDNAME} &c[Moderator]&f {DISPLAYNAME}&7:&c {MESSAGE}'
Note: the name you write before the '{WORLDNAME}' has to be exactly how you spelt it in the groupmanager file.
Hope this helped, hard to explain like this but if you need more information pm me.

It's fairly simple. First, get the plugin PermissionEX (or pex).
Second, go to the plugins page for the plugin you wish to add perms for players from. Look for their perms list. Copy paste the perms in like so under permissions for sed group.

- example.plugin.blabla

Watch YOUTUBE to, it's you're best friend with this stuff.

I would do it for a rank just give me the ip then I will help you

Learn to use PEX.
I Can also do it for you, for $15.
Add my Skype if your interested.
Found from my Profile/Signature.

i would recommend group manager as it is easier and i think it comes with a pre-made permissions. But if you want to use permissions you can.