Here are some links:

Link to the CIS120 page
Link to a file in a subfolder
Link to the first page about links

Note that the first example gives the entire address to a page on the web. The second looks in a subdirectory called subHTML5 to find fileInSubHTML5.html. The subdirectory is in the same folder/directory as the original page. The third example simply links to another page in the same directory.
Note also that a when a paragraph ends, a blank line is inserted.