Make sure that the machine is connected to your computer and powered on.
Launch a scan application such as xsane or simple-scan(If it's not installed, please install it manually to use scan features. For example, you may use "yum install xsane" for rpm package systems and "apt-get install xsane" for deb package systems to install xsane).
Select your device from the list and set the scan options to apply.
Click the button.