Blocks are the building blocks of workouts. These will be the sections of a workout. Think of blocks as the warm-up, power, core, strength, and metabolic breakdowns of a workout. You can create blocks to add to workout programs. Building Blocks is for groups of exercises that use on a regular basis so you don't have to start with nothing in each workout.
You will want to title a block along with adding a description for a client.
Here is an overview of a created block that can be added to a workout.
When you go to create a workout, you can now add any block you have created into a workout.