First, I want to add a user. So how to do it?

+ To add user:

sudo adduser <username>

to add password for your user

sudo passwd <username>

+ How can i switch from one user to another one? In this example, i want to switch from one user to another one.

su <username>

and type in your password to login

after that, you will be at a ‘$’ prompt. type:

bash

to get to a normal prompt.

+ How can I delete a user?

sudo userdel <username>