I had never taken apart a 3-way light switch before, and it wasn’t immediately clear what was going on in the box. Once I figured it out everything works perfectly, and I am using each one in two separate rooms rather than installing both of them for the same light. All functionality works perfectly, both manually and with the Kasa app, for both lights when the switches are installed on seperate circuits.In my photo, one black cable was hot (the line) and that’s connected to the black screw labelled line/load. The other black and the red are the travellers. On my other circuit the travellers were red and white. Some tips...1) Install both to control the same lighy only if having matching switches is important. They look very similar to the switches I already had, so this wasn’t important for me at all. You absolutely only need to use one smart switch per circuit.2) Power only goes to one light switch. I installed them on the switch that had a power coming to it.3) You can find which one has power (is hot) by disconnecting all cables from both switches, and use a multimeter to test each cable. Only one, on one side, will be hot. It’s best to turn the breaker off before detaching the switches, and then turn it back on to find the hot one. It should be one of the black ones.4) To be sure which are the two travelers, again with the breaker off, you can use a wire or something to connect all of the cables together in the box with the hot cable, then go over to the other side and again use the multimetre and both travellers will be hot.5) The cable on the other side that is not hot at this point will be the one that goes off to the load, which in this case are the lights. It will probably also be black.6) Back in the box with the hot cable coming from the breaker, connect the hot wire to the black screw of the smart switch, and the two travellers to the two travellers screws.7) This could’ve been tip one, but you need a neutral to connect to or it won’t work. This is required so there is a circuit always delivering some power to control the electronics in the smart switch. It will work if you connect neutral to ground, but this is not recommended at all. Connecting the ground to the ground is optional, but recommended.8) Reconnect all cables to the original dumb switch on the other side. The load should connect to its black screw. If it has a neutral, and you want to use both smart switches on the same circuit, then go right ahead.9) Take a couple of clear pictures of both switches BEFORE disconnecting any cables so you can be sure to put it back as it was. You could’ve also added labels (included in the box) as you confirmed what each cable was.10) When setting it up in the app, after you have configured the smart switch following the instructions, just click next/done a couple times to tell it you did the other one, on the other side, when you actually didn’t.11) Install the second switch on another 3way circuit of your choice12) To work with Google Home/Alexa, you need to turn on remote control in the device settings using the Kasa app. This is because Google talks to your TP link account in the cloud to control the lights.Final note: It really is too bad they don’t sell these in packages with only one for people who might want to only install one on a single circuit . Their included information could also clarify that each switch could be used on separate circuits. I hope these tips help someone.