How to open the Block Diagram template. This animation is a simplified view. In the practice session coming up, you'll see many more shapes than you see here.
Visio offers a couple of templates to use when you create block diagrams. The most obvious choice is the Block Diagram template.
Click Play to see an animation of how to open that template.
The Block Diagram template provides several stencils, including the Blocks stencil, which contains boxes, circles, diamonds, arrows, and other useful basic shapes.