Step 1:
Use your mouse to highlight the text you want to be a link
.
Step 2:
Next go to the toolbar at the top of the window and click on the “link” button.

This will open a new window – the link properties window.
Step 3:
Type in the URL in the window and click O.K.
Internal Links
Step 1:
To create an internal link, first make a named anchor:
Place your cursor where you want to put the anchor (example: if you
are creating a "Back to top" link, you will put the anchor at the top
of the page).
Step 2:
Next, go to the menu item Insert > Named anchor.
This will open a new window where you can type in the name of the anchor. Name it something simple, like "top."
Click O.K.
The little yellow anchor icon that appears is the named anchor (the icon will
not be visible on the web).
Step 3:
To link to the named anchor, place your cursor where you want the link to exist
(example: if you are creating the "Back to top" link, you will make the link
at the bottom of the page).
Next, highlight the text that you want to make into a link with your mouse and
click on the “link” button on the toolbar at the top of the window.
Step 4:
In the Link Properties window that will open, type in #titleofyournamedanchor.
The “#” sign indicates that it is a named anchor you are linking
to.
Click O.K.