Once you have created Folders in your Library, you have the ability to control when your students have access to the Folders by using the share/remove feature. This allows you to create all of your Folders ahead of time, and then share them when you are ready for your students to have access. You can also remove the Folders if they are no longer needed.
To remove a Folder, select the Small Group in the left side panel, then click on Folders in the middle tab. Then click on the icon next to the Folder you which to remove, then click Unshare.
Once you have clicked Unshare, the Folder will no longer be shared with your Group or Small Group.
Note: You can follow all of these exact same steps for your Small Group Folders.