Heya!
I suggest that you firstly download CoreProtect. This plugin allows you to track chat/click/break/command/block/session logs of all players that join your server. Then after, regarding your staff ranks: add the corresponding permissions.
Admin
- IP Ban
- CoreProtect Rollback (to undo griefing issues)
Moderator
- Ban
- Mute
- CoreProtect Inspect:-
- all actions listed in the plugin
Helper
- Temp Mute
- Kick
I suggest using a permissions plugin like Luck Perms to link the staff ranks together and to inherit the permissions of the previous staff rank. e.g Trainee > Helper > Builder and as such.