Change the look of Navigtor

Hmmm, maybe I'm blind but I couldn't find anything about how to change the look of the photo navigation. If I want to include this into my theme, do I only have to copy the navigator.tpl into my theme folder? And edit this file? Or any other file? ...?

What I want to do: I want to exchange the next/previous texts in Siriux theme with arrows and also show first / last arrows. And if it is the first or last one all arrows shall be shown, but only the sensefull ones clickable. I think this should be easy to do, but I'm completely confused at the moment...

Cheers