I Need Some Blogging Help

I am wanting to make my blog to have more of a scrapbook look to it. I have no idea what I am doing. I want to change my backgrounds to some files I have downloaded on my computer. How do I do that? I have messed around with it for a half hour and can't figure it out. Can anyone help me? It seems there was a website that gave step by step directions. Does anyone know what that address is? Any help you can give me will be greatly appreciated.