GN4 permissions are flexible and configurable, covering almost all aspects of the publishing and configuring. It makes them powerful, but also complicated and sometimes difficult to apply in the correct way.
Direct and inherited permissions
On some GN4 items you can set permissions directly, and that is fairly simple and easy to understand. For example, you set permissions on an object library in the way that only you can access it and nobody else.
The items where you can set permissions directly are listed in On which items you can apply direct permissions?
It becomes more complicated for items that inherit permissions from other items. The items that inherit permissions are listed in Which items inherit permissions?
Moreover, some items inherit the permissions but can have the permissions set also directly, e.g. editions, that have direct permissions, but also inherit permissions from the parent title.
Items that require the Default permissions to create them
Some configuration items require that you have the Default permission to be able to create them. An example is a print queue. If you do not have a default permission, you cannot create it. The list of items you can create only with the Default permission is in Which items you can create only with the Default permission?
Permissions of "container object" and "contained objects"
See About "container object" and "contained objects".
General warning related to permissions
The system may behave quite differently if you log in as an Administrator, or if you log in as a non-administrator user. See Difference between administrators and non-administrator users for more details.