To make an underlined link in a page of HTML, surround some text with a pair of A tags. The A stand for "anchor", and the enclosed text is called the anchor text of the link.
Inside the angle brackets of the first A link of the pair, insert the HREF attribute after the name of the link. The value of the attribute (written after an equal sign, and within a pair of double quotation marks) specifies the destination the link goes to when the user clicks on the anchor text. Here are two examples:
Click here to see my other web page. This link leads to another page in the same directory, on the same server, as this one.
Click here to see the home page for this course. This link leads to a page hosted on a different server.