Open Facebook and go to your News Feed
Tap/click Groups in the left menu (or search for your group name)
Select the group you want to delete
Click/tap the group name to open it
Click/tap Manage (for desktop) or the group settings/options (for mobile)
Click/tap Settings
Scroll to the bottom and find Delete Group
Select Delete Group
Confirm by typing the group name (if prompted)
Click/tap Confirm Delete
Wait for the deletion to complete and verify the group no longer appears