The help command is a useful command for finding the invocation, permissions and aliases for a command. It's similar to the docs except it doesn't contain every command and you need to know the command you want help for.
Glass: Manage messages, Add reactions
The add reactions and manage messages permissions are used in very specific situations. To gain more help on a command or sub commands, these permissions are required.
h, commands, cmds
If command is specified, it will show how to invoke the command along with what permissions are needed. If a command group is specified, e.g. config it will show all of the sub commands available.