If you want to create a link from some text to another page (and assuming that the text is in a copy of the Text/HTML module):
- Edit the module's text
- Highlight the word or words you want to turn into a link
- Select the link tool from the editor's toolbar (it has a chain link in the icon)
- use the options there to choose the link (if you want to link to a page on the site, choose that option, and choose the page)