How to Use Groups Finder
Follow these steps to use groups finder :
1. Click “GROUPS FINDER ” Feature
2. Type keywords what do you want, then click “Find Groups”, wait until finished
Click “show more” if you want to see the next group list. as you can see, you can get emails from closed groups though. You can also directly get UID members from all the groups that appear in search results by clicking “Extract Member UID”
3. This is How to Get UID from Group Finder, Select Extract Members UID
4. Check the Group page, is it really the Group Page you want and check the number of member
To check the group page, you can add UID member to url https://www.facebook.com/groups/ then open it.