Hello, I need help installing a 3 ways switch (hs210 kit)

in my box I have 5 black wires, 1 red and 1 white. Of course I put the white with the white. (upstairs)

In the red circle these are my 2 lights and I have a black wire which gives me power.

Where do I put the other 3?

On the other switch I have as wire: 1 red, 1 white and 1 black (downstairs)

here is an image, other switch working fine in this picture, is control other light