When creating a workout plan, you can use your tags as a filter when searching for exercises to add.
Here's a quick overview, and you can get the step-by-step breakdown below:
Make sure you are using the Day View in the Workout Plan Creator.
Use the "Add multiple exercises" link to open the advanced search area and use tags.
Click the drop-down arrow to open the filter options and see the Tags search area.
Here is what it looks like when expanded:
Click into the "Tags" field to view and select any tags you have already created.
Note: You cannot create any new tags here.
Click the "Search" button, select your desired exercise(s), and then click "Add Exercises to Workout."
Click any exercises you want to add to the workout, then click the button to confirm and add the exercise(s) to that day's workout.