To add contacts from a private group into a public group, you will first need to create the new public group. This can be done by clicking on the "New..." drop down that appears in the top right hand corner of the screen and select the "Group" option.

Enter a name for the group, check off the "Public" check box and click on the "Create" button.

* Note that you will need to have permission to create public groups, otherwise you won't be able to see the "Public" checkbox. See this article to gain permission to create public groups: Assign Permission to Create Public Groups

Next, load up your private groups by going to the Org View tab and finding the group under the list of departments that appear in the list on the left hand side of the screen.

After finding and selecting the private group, simply clicking the “Search” button will show all of the contacts in this private group. From here, you will want to click on the checkbox to select all contacts in the group.

Next, click on the “Copy into Folder” drop down and select the public group that will hold the contacts that you are copying from the private group (the public group that you created earlier.)

Clicking on the group name from the drop down will copy all selected contacts into that group. You will a message like so at the bottom of the search once clicked.

Find the public group to verify that the contacts have been copied in successfully.