The very first site I programmed was a fluid html 4.0.1 compatible PHP and MySQL driven site. I didn't know anything about HTML, CSS, PHP or MySQL. In retrospect it was too much to try to learn all at once; although I was successful, just took me a looooooooooong time.
I would not copy a site. Copying doesn't teach you anything. Look at the content you have for your site and prioritize this into most to least important. Once you done that think semantically what you have. What is your page title, put this into an <h1> what sub sections do you have? Name these with <h2>, you may have other sub headings so use <h3><h4>... What paragraphs of info do you have put these in <p>. What lists do you have use <ul> or <ol>. Once you finish this you will have a very basic website with all your info.
Then decide how you want this info organized on the page. Find other examples of layout that could accommodate your content. Then use C.S.S. and as little of extra html markup as possible to try to lay-out your content in the same way as an example you liked.
Ask questions along this path as you run into things that are frustrating you. Don't try too much in one fellow swoop. Try a change, if it works, proceed, otherwise, revert and try something else.
Hope this helps,