Are you using a SCART or HDMI cable?
Please check if the cables are connected firmly not damaged or corroded.
Check that the GV101YRH Freeview High Definition Digital TV Recorder is switched on, a green LED will show on the front of the unit. When the unit is in standby mode, a red LED will show.
When the DTR is switched on, use the (INPUT or SOURCE) key on your TV's remote to select the correct HDMI or SCART input. Many TV's have more than 1 connection.