I have 2 sets of wires with 3 wires at each location. I know which wire is the hot wire coming in (only 1wire at box #1). Other than that I'm not sure where to connect the other wires?

I need to hook up a 3-way sensor at both switches. My switch locations are at separate locations on a 1st & 2nd floor. Therefor I need a sensor at both locations. Will the PR180 leviton 3-way sensor switch work for this application?

I did a search for PR180 in the electrical forum because I remember others having questions and issues with the PR180 used as a 3 way switch.

Here are a few, they may help, there are several others, you can use the Search Utility on any page of Ask Me Help Desk, use the advanced to get to search the electrical forum only.

Hope this helps.
https://www.askmehelpdesk.com/electrical-lighting/can-you-use-2-3-way-leviton-pr180-motion-sensors-together-42731.html?highlight=pr180

https://www.askmehelpdesk.com/electrical-lighting/wiring-leviton-3-way-motion-sensor-switches-21225.html?highlight=pr180

https://www.askmehelpdesk.com/electrical-lighting/installing-3-way-motion-dector-light-switch-4-wires-48061.html?highlight=pr180