Thinglink Overview
Thinglink, a website with a free teacher plan as well as several paid plans, allows all of its users to upload graphics, including PDFs, and add "buttons" to those graphics. Those buttons--which come in a variety of shapes such as magnifying glasses or simple, red dots--create an interactive image for the viewer. These interactive images' buttons, when scrolled over, reveal text, a video link, or pictures. Educators can use this program or have their students use the program.
Tutorials
Thinglink so kindly provides a tutorial just for educators. This tutorial is not a video, but it is a series of helpful screenshots.
A YouTube user and teacher, Kate Peila, created a helpful tutorial on her blog Purely Paperless.