How2 insert logo and change colors

Hi,

I just started using Wordpress and installed the Montezuma theme. I wanted to change some things:
1. replace the Site Title and Tagline with a logo ( a picture)
2. change the colors of the background, from white to another color
3. change the colors of all the fonts, from black/blue to another color

I know I have to use the Montezuma Options screen, but I don't know what I have to change. I have some basic HTML/CSS and PHP knowledge.

If someone can help I appreciate it!