Change order of category

Hello, first of all I am not sure which version of wordpress this is!

My question is, I have recently transferred at http://www.randombytesfromlife.com, and I have changed the theme to wpcleangreen. Now as this theme supports category wise posts, I want to change the order of the categories as they appear. The ones with top priority be placed on top whereas other at the bottom! Can you tell me how I can do that?

Also, I cannot place the menu line anywhere.. i cant see it at all and I am experiencing issues with going back to the homepage without it. Pls tell me what to do in both cases..Thanks