I'm currently taking a class on it and have dabbled a little bit with it. A website mostly consist of simple HTML coding and you can find this all over the web. You also need to know how to format pages with basic headers and neccesary phrases (<html>, </html>, etc.) You also need to know how to manuever images on your page (float, p tag, etc.) and again you can find tutorials over the web on this. Besides this to get design you need to be able to write css which again is all over. On all of this you can copy and paste from designs you like on the web. I would reccomend sites like:
Hope this can get you started let me know if you have any questions