HTML - Trying To Get The Ball Rolling

Well I purchased my webdomain and hosting package months ago and have yet to make any progress on my project. I have read like all the tutorials on w3schools. There is still just so much that I just can't seem to get figured out.

I know my page has to be written in php.

Now I want to at least accomplish a basic layout for my page within the next few days. I don't quite understand the whole Css Style Sheet Thing. We will use www.bestbuy.com for example .. See the top bar there with there logo then down to the search engine. No matter what page you go to that is the exact same. I am just trying to get atleast that accomplished on the site for now. I will need 9 drop down menus just like they have there. I want the top really basic as it is there. I will later be adding a userlogin and such. So would I photoshop My sites logo seperate, Then make my drop down buttons all seperate, and make the header background another seperate image ? Or make them all in one file ?

The second question is that I use ww.fatcow.com as my webhost. Do I add pages to my site by naming them like page2.php so people do like www.itemraffle.com/page2.php or do I have to purchase there unlimited subdomain package also for $25 a month more ?