Hi, I'm trying to wire an HS200 as a single switch that controls two outside flood fixtures. The original switch has 4 black wires attached and no other wires. In this scenario, am I essentially wiring the two groups of black wires to one of each of the black wires on the smart switch?

There is a grouping of white wires deeper in the box. I assume I should attach the Kasa white wire to those?

As a side note, what's the deal with the black wire that's attached inline?

Thanks!