In order to tear down the lab environment, you simply delete the workload and the custom lens you created.
Select Custom Lenses on the left navigation:
Select the radio button next to the Custom lense we created and then click the Delete button.
Confirm the deletion by clicking the Delete button on the dialog - with correct custom lens name entered:
Once the custom lens been removed from your AWS Well-Architected Tool, you might see a warning message on top of your workload list:
Input the full name of the lens for the confirmation, then you will able to unapply a custom lens for this workload review.
If you want to delete the workload, please check the radio button on workload list, and click the “Delete Workload”. Or you can follow the instruction in Lab: Walk Through of the AWS Well-Architected Tool .