For example, your Facebook group is found in this link:
https://www.facebook.com/groups/363927216972942/events
The group ID is the numerical part of that link. In this case, the Facebook group ID is:
363927216972942
https://www.facebook.com/groups/363927216972942/events
The group ID is the numerical part of that link. In this case, the Facebook group ID is:
363927216972942
Published on: 10 / 01 / 2019