How to go between groups with permissions.

I'm still getting my head round permissions. I understand that each plugin gives you a few little things such as in Towny you have things like towny.admin, towny.town and so on.
I understand that you are supposed to write up a few groups in permissions.yml.
What I don't understand is how to let users go between groups. I have no idea how to do that. Are there commands? Plugins? I don't understand.

 

Here are some links for you to undertand but permissions.
I saw this thread some where again with the same question.

any way here,
My Personal Permissions Info: http://forums.bukkit.org/threads/read-first-permissions-information-pex-bperms-permsbukkit.84151/

UGP http://forums.bukkit.org/threads/the-ultimate-guide-to-permissions.80291/#post-1161143

PB http://forums.bukkit.org/threads/tutorial-for-permissions-beginners-updated.21921/

Perms FAQ http://forums.bukkit.org/threads/permissions-faq.25080/
PEX Link's http://forums.bukkit.org/threads/tutorial-for-permissions-beginners-updated.21921/
PEX Super noob friendly http://forums.bukkit.org/threads/tutorial-how-to-install-use-permissionsex-noob-friendly.50962/

Bpermissions Links
http://forums.bukkit.org/threads/st...oob-level-99-tutorial-for-bpermissions.55315/
http://forums.bukkit.org/threads/bpermissionsgui-a-gui-editor-for-bpermissions.56446/

 

Oh yikes! You mean there's all that to learn? Won't the permissions.yml do?

 

just read the UGP and the PB. its easy juts just that people dont know how to format it.