4.5. Access and utilize the router to set basic parameters (including CLI/SDM)
If you boot a router, the interface status messages appear, and you press Enter, the Router> prompt will appear. This is called user exec mode (user mode), and it's mostly used to view statistics, but it's also a stepping stone to logging in to privileged mode.
You can only view and change the configuration of a Cisco router in privileged exec mode (privileged mode), which you can enter with the enable command.
You now end up with a Router# prompt, which indicates that you're in privileged mode, where you can both view and change the router's configuration. You can go back from privileged mode into user mode by using the disable