Calendly

Overview

You can use your Salesforce sandbox environment to test, customize, and finalize changes to your Calendly package without affecting your Salesforce production organization.

Once you connect your sandbox account and install the Calendly package, you can test your Calendly flows by scheduling and canceling Calendly events. When you’re happy with your setup, you can disconnect your sandbox and integrate your production organization.

https://help.calendly.com/hc/en-us/articles/360055747033-How-to-install-the-Calendly-package-in-your-Salesforce-sandbox-environment#How-to-connect-your-Salesforce-sandbox-environment