Big Cartel Themes/Customization?????, wow...can't seem to figure Big Cartel out at all.. Options

[shutterleftopen]

I'm trying to do a big cartel layout for a clothing company that i've been working with. i know css and html. but for some reason i cannot seem where i even start on a Big Cartel site layout and/or theme. i've seen that i need to download the theme in my case it's the "sexy" theme, and then customize it in dreamweaver and put it on the pages. everytime i try and put in a banner or navigation at the top on the page code section it places it inside the product space..any help on where to find info on getting started with doing a custom layout/theme would be extremely appreciated..thanks.