I'll try to keep the tone light because I hate writing dull instructions as much as you probably hate reading them. For those that must have them, commandments on stone are available from department administration on request. This will give me a chance to explain the system. Email stands for 'Electronic Mail' and is roughly analogous to regular post except that it often arrives sooner and has only slight physical presence. The latter means that you can store it or even print it, but you can't send a fruitcake by email.
Email exists, except in isolated networks, entirely on the Internet.
If you picture a stock exchange, you have the general idea. I often think of the Internet as a great cloud of dust generated by all the computers trying to communicate simultaneously. Now, we can reach into that cloud, the Internet, and find any particular computer, if we know its address. But an Internet address means nothing to us. We would never be able to keep track of them all.