A hyperlink is a link that you can click on which points your browser at another web page outside the manual itself - most browsers nowadays open hyperlinks in a separate window, or a separate "tab" on your browser.

To place a hyperlink in a Tiddler you are Editing just follow these directions:

The simplest way is just to copy the URL (the "address") of the page you want to hyperlink to from the address bar at the top of your browser, and paste it into your Tiddler!

To do it in a slightly fancier way (good if the URL is very long and doesn't really describe what the page is that it refers to) you can open double square brackets with the name or your own description of the page you are linking to, followed by a vertical line ( | ) and then paste in the URL, and close the double square brackets. So in the Edit mode of the tiddler it would look like this:

[[The website of the Royal College of Psychiatrists|http://www.rcpsych.ac.uk/]]

Once you have clicked "done" it will look (and work) like this:

The website of the Royal College of Psychiatrists