How To Create New Template

I want to learn how to make my own templates for this cart as I love it. But I am at a loss for where to begin looking at folders, pages and code.
I don't want to piss anyone off, but I know a good bit about editing, changing Joomla templates, but I have never worked on anything like this cart, (Which I love to death)
Could anyone please, just post a 1,2,3, very basic guide to where to start, what folders,files to look at for changing, creating a new template?
Like-
1. root/cart/somefolder/somefolder/somefolder/somefile=Layout of the front end.
2. root/cart/somefolder/somefolder/.....

Not asking for total instructions, just where to begin...

Asking what folder and files, and basically, generic step one, step 2 step 3...
All generic, generally speaking.
I know I can do it, but just not familiar with this setup.

Thanks for anyone who offers up some tidbits of knowledge.

Look at this explanation of the Opencart framework here... it will give you an overview of where everything is.
http://forum.opencart.com/viewtopic.php?f=20&t=4113