Go the "Newsletters" box and enter your email address. You will get an email with a download link. Download and save to your hard drive. This is a fantastic beginners guide with lots of stuff for the rest of us. .... b

By the way there are some fantastic images at this site. True to National Geographic tradition - the best that there is. Can be saved for your own use. No copy protection. 

http://photography.nationalgeographic.com/photography/

Photo below demos image size capability. Even greater image size is available.