How do you design/modify styles?

[Doctor-Who]

I apologize in advance if I posted this in the wrong section..

I was wondering what software I would need to design a style or modify an existing one. What I'm mainly interested in is how to add buttons to the navigation bar of an existing style, I really like the Hardwired style I found here but I would like to add several move buttons, one to link back to my homepage and one to link to my gallery and possibily one more in the future. I may end up having a custom style made, but I'd still like to know how to add buttons & other items to my styles.. Sorry for being such a newbie..

Thanks in advance..

[gfxhavenowner]

Post people use Photoshop for graphics, and just fool around with the templates in the AdminCP.