Buffalo TeraStation Live HS-DH-TGL/R5 User Manual page 6

After your TeraStation has completed booting up, check
the LINK/ACT LED on the front of the TeraStation. If
it's lit, then your TeraStation is connected properly, and
you can go on to page 8. If it's not lit, turn to page 7 for
troubleshooting.
TeraStation Quick Setup
Press the power button on the front panel. LEDs will
light as your TeraStation boots up.