How can I make my group private?

Navigate to the drop-down menu by clicking on the left side of the "Groups" option.

Click on the "Create Group" option with the + sign on top right side of the page. 

A pop-up window will appear, prompting you to create a new group and provide the required information.

In this pop-up window, you will be asked to select the group type. You can choose 'Private' if you want to make your group private.