LINK
The Link Dialogue box is a very widely useful tool, in my humble opinion. Not only does it allow you to type in the link (file or URL), but it allows you to browse for the file on your hard disk. If the file is in a directory other than the directory of the file you are creating, you will have to type that directory in. You can also specify a default directory, if needed in your preferences (under the File pull-down menu).
You can choose from three types of links:
HTTP
Named Anchor
None

If this is a link to another web site (http://www, etc), you will need to type in the www address & then click on the HTTP radio button. The program will automatically supply the 'HTTP://', as well as all the other link tag parts for you.

If this link is to a Named Anchor within this document, you can either type in the name of the anchor, or choose the anchor from a pull down list of all the Named Anchors on the page ('grabbed' for you automatically), and then click on the Named Anchor radio button. This provides all the appropriate HTML tag syntax for you.

Also, if you are creating a link which will be used in a frame, then, the optional 'Target Name' text box can be used to supply the name of the target frame in which you want it to appear.

And last but not least, if you click in the 'None' radio button, the default link, not referencing a named anchor or an external URL will be used.

As with most of the other items, the Link command is available in the formatting pull-down menu as well as the HTML Toolbar.