Here are a few pointers that should get you on your way. Back in the 60's, the US Government developed a network of powerful computers to communicate military and scientific information quickly. As this network developed it grew to include colleges and schools, and a simple computer language was developed to make information on the Internet easier to read, and easier to find related information. This was a benefit to researchers, who could link their work and writings to the writings of other people so readers could understand their ideas better. Since then the web has grown to include graphics,animation and sometimes video and sound as part of web or HTML pages.
Links can be text or images.
We've used both in our site. The easiest way to tell if something is a link is to move the mouse over something.