Metro 18 watt TMB high/low input hookup

[dcburn]

Hey guys, rookie builder here, only built a 5f2a previously. Anyways, from the metro 18 watt TMB diagram, I’m having a bit of trouble understanding how to hook up the high and low inputs. I have them connected together, but im not sure how I connect them to V1.
And do I need those square lugs at V1 to hook up too?
That gray wire with the red, not sure where that actually gets soldered on?
Same as that second wire to the other input, shows red and ground at input, but just red wire in the other square lug at V1?

Any help would be so appreciated