To be able to check all links between your files, and to be able to insert a link via a file dialog, you must set your Home Page folder. The idea is that this folder, together with its subfolders, should contain all your html files, and be a mirror of your home page at your server.
The Home Page folder is set via the menu Config -> App Paths, as shown in the picture below.
To be able to check all links between your files, and and to be able to insert a link via a file dialog when you use the BASE element, you must set the URL to your server. This is set via the HTML Utilities menu. In the dialog box there are two field "Server URL" and "Path". If the URL to your home page is http://www.somewhere.net/~myplace/ then set things like this:
The URL has to be split in this way for HTML mode to correctly deal with relative URLs within your server.
