1. Open a terminal and start with "su" (password will be asked)

su

2. Next open "/etc/sudoers" so we can edit it

nano /etc/sudoers

3. Add the user you want to give sudo privileges (where "hans" is the username - I placed it right under the same formatted line for the root user)

hans    ALL=(ALL:ALL) ALL

4. Save and close (CTRL+X, confirm by pressing "Y").

You should be good to go now.

Test this with for example:

sudo ls