Before you search for your groups, make sure that you’re in the organization view instead of the public view.
Go to Groups and click My groups.
2. Click Switch organization view to "yourdomain.com".
This means that the groups you see and join will be within your organization, and not public.
To search for a group, at the top of any Groups page, type a word or phrase in the search box. To help you search faster, Groups suggests search terms as you type. Click one of the suggestions to open it, or click Search
to see a list of results.
You can subscribe to any group in your Groups directory that's open to new members. Some groups let you subscribe directly, while others might require you to send a request.
In the Groups directory, click the group to open the group's page.
On the group's page, click Join group or Apply to join group.
Choose how you want to read messages that are sent to the group, whether or not to link to your Google profile and show your picture on posts, and the display name you want members to see. Then click Join this group or Apply to join this group.