rewriting category url

Hi,

I am using the Sliding door theme and have the images linked to categories. All works just fine.

What I would like to change, though, are the URLs in the address bar, for example from https://interculturalzone.lokahi-interactive.com/?cat=16 to https://interculturalzone.lokahi-interactive.com/about

and so on.

How does one do this (in the easiest way possible)?

Thanks