Brother MFC-3420C - Manual (Page 64)

3 - 7 USING THE BROTHER CONTROL CENTER
Performing an operation from the Control Center
screen
If you see this screen it means you left-clicked a button in the Control
Center window without first placing an original in the ADF.
Place the original in the machine’s ADF, and then click OK to go to
the Control Center screen.
If your machine is flatbed model (MFC-3420C or MFC-3820CN),
and want to scan the original from the scanner glass, please use
( Scan ) on the control panel of the machine.