Beginning a Template

I am a fairly knowledgable teenager and i have been into web design for a year or two now. I can make some very nice HTML sites with Dreamweaver and Photoshop but for my personal site i wanted to branch out and have more of a blog feel so i looked around and found wordpress. Now i’m totally lost in all the settings and code. I understand have CSS works and the divs and aligns and such, but i am by far not fluent in it. My question is… what’s the best way to learn how to make a custom layout in wordpress? I have gone through most of the documentation but it’s very spread out… it seems i cant just go to one thing in my themes panel and change it to get what i want (such as a custom header or to remove my sidebar). I am curious if i can just make a CSS page as my template then insert the loop into it for the content (and make the content area fill 100% vertical so it sizes correctly when more posts are added). I also have been trying to take out the default sidebar and have had little luck as it is referenced in about 30 different places and i have no idea which one i need to delete to remove it. Right now i have all the text and searchbar gone but the gray background is still in and all my content text aligns to the left of the now deleted bar (which still takes up space). Any ideas would be greatly appreciated as i am trying my best to learn but feel there is a lack of user frienldiness in wordpress.

Thanks