Simple instructions how-to create a link (aka hyperlink) to another page...
In the editor, type the text you want to be displayed and then select it by clicking and dragging from the left, to the right.
When the text is selected, click the 'Insert/Edit Link' button, eg:
The 'Insert/Edit Link' dialog will popup. Enter the hyperlink URL in the 'Link URL' field and click 'Insert'. If you do not know the hyperlink URL then you can visit the page, then copy & paste it from your browsers address bar. Here is an image showing the 'Insert/Edit Link' dialog box:
Save the page or article you are working on and you will have created a link!