How does home theatre pass through work?

If I use a two channel preamp with HT pass through, does the signal go through the HT processor first? The cables connect to which inputs and outputs? Does this degrade the sound? Thanks for your help.
In that type of setup...everything in regards to two channel reproduction will be connected directly into the two channel preamp...the prepro will not be in use at all.

Hometheater and anything else you choose to connect directly to the prepro will function as always...the signal will pass through the preamp...the preamp will not be active.

You will need to connect the prepros L+R preamp outputs into the two-channel preamp pass through inputs.

To add a bit to the discussion, when in HT pass mode, most pre-amps go into "Unity Gain" mode which simply means that the volume control of the preamp is neither attenuating the signal, nor is it adding gain. It is as though the volume control has been removed from the signal path.
OK, got it. Thanks!