Clicking on the lesson's title will open it in this box. The lessons are in PDF format, so you'll need the free reader. If you don't have it installed, you can get it here. The bottom of the screen has Bible Gateway's passage lookup feature already open for you to look up any scripture you're studying. When you're finished with a lesson, click on Lessons on the top menu, and you'll come right back here.
Tip: You can maximize your screen size by pressing the F-11 key.