Hi ..
If i unplug the AVR then i can't watch TV since its directly connected to the AVR ?
If you have everything wired correctly, you can watch TV w/o turning on the AVR.
Your cable/SAT box is wired to the AVR.
Your DVD/BDP is wired to the AVR.
Your AVR is wired to your TV, (via ARC if your TV has it).
"Through function" means your AVR will still pass the cable/SAT/disc signals
through the AVR to your TV with your AVR turned off. You'll hear the audio from your TV speaker(s).
If you turn on the AVR, it will take the input signals and process them to your surround speakers.