looking for a comprehensive tutorial on how to change the theme to my own

Hello,

My first post here and my first time with wordpress. I’m looking for a good tutorial on how to change the look of the word press to look more like my own site. I’m a web designer myself, but I just need to know what files to update, and every detail I must follow. Can this even be done? If it can, is there some documentation written for webmasters without all the extensive explanations?

Thanks in advance,