needsinfo

I know there are a lot of threads on this, but i am getting a lot of mix answer by reading through all of them and some of them are not clear to me.

What i bought:
Kenwood KDC-BT318U
http://www.sonicelectronix.com/item_...DC-BT318U.html
Metra 71-8112 amp integration
Scosche LS2081B / LS2081( install kit)
http://www.sonicelectronix.com/item_...1B-LS2081.html

I already installed the new stereo,it turns on but there is no sound.

Questions:
1. IF i connect everything correctly should i be getting sound?
2. Does the factory amp work without the factory stereo?
3. Does by passing the amp mean not using the amp at all? where we connect the speaker wires (output) from the back of the stereo to the speakers wires that go directly to the speakers
or
Does by passing the amp mean connecting the the speaker wires (output) from the back on the head unit to the speaker wire input of the factory amp?

Can some one explain which wire is out put and which is input?



So in the picture i took off someone else post, I wasn't sure which wire was input and out put for the amp.

Thank you.