The Managing Sandboxes option can be accessed using the dropdown arrow in the Org section (top status bar).
Selecting this option will bring up a screen containing a list of Sandboxes. You may add or remove sandboxes using the controls in this screen.
To Add a Sandbox, press the Add Sandbox button. This will bring up the dialogue window.
From here select any Sandbox in your organization and the Confirm button to continue.
Good to know: If you have recently updated your Sandbox, Salesforce may change the Sandbox ORG ID. This will result in the updated Sandbox appearing as a DataGroomr Trial. To resolve this, remove the existing sandbox, press the Refresh button and re-add the sandbox.
Note: Your Salesforce user profile has to have "Manage Sandboxes" permission in order to be able to search sandboxes by name. You are still able to add a sandbox by entering its ID if you don't have this permission.