How to create Customers login, Users or Clients

I don’t see an options where i can add Customers (Clients) so they can login and submit their tickets.
I see there is a button customers but i don’t see i can setup there a login for them only mail on contact.
What i want is creating Customers so they can login and see their tickets opened closed and whatelse desk offers.

Can i have some tips please

Start here Customer Portal