To get Font Awesome fonts working in Lectora, you must first download and install the font on your system (so you can see them within Lectora). To do this, click here and click"download". Once downloaded, install the FontAwesome.otf file (right-click, choose "install").
To add a Font Awesome icon, go to the Font Awesome cheat sheet and highlight the font icon you want. Paste into a Lectora text box, then select the icon and choose "Font Awesome" from your font drop-down menu. You can then adjust height and color to suit.
This .awt file imports Font Awesome as a web font, so you should be able to see the sample icons below in the html folder without actually installing the font (see "custom.css" for code).