1. Highlight the word or phrase you want to link
2. Click the link icon in the toolbar
3. Type in the URL you want to link to
4. Select the target
New window: will open the page to a new tab when selected
None: it will open within the same tab when selected
5. Click on Ok
6. Your linked word or phrase will now be linked
Once linked, the word and/or phrase is now blue and underlined.
7. Testing out if it links properly
Two ways to do this:
Holding CMD/CTRL on your keyboard and clicking the link in the editor
Opening up a preview link of the current draft and scrolling to the page.