@ChloeS 

Yes, set up smart actions so when the switch changes it will control the bulbs. Here is a FAQ for reference: https://www.tp-link.com/us/support/faq/2567/

@Tony Thanks so much! My husband is still suspicious, and found this thread which implies that as of Feb 2020 this user could not make the smart lightbulbs and smart lightswitch talk to each other. https://community.tp-link.com/us/home/forum/topic/109497 (see last comment by @BeegJawn). The set-up that @BeegJawn is seeking should work for both dimming (assuming you have the dimmable smart lightbulbs) and turning on/off at the smart light switch, correct? Is he just having technical issues that should not be happening?

@ChloeS 

They will talk for sure so after setting up the smart actions, if you were to physically press the smart switch, the light will then turn on. If you wanted the switch to control the brightness of the bulb, that is something different, in which you would not involve the switch, and just control the bulb itself. That can be setting a schedule or create a scene for the bulb. 

@Tony Thank you again. So to be clear, in our situation where the lights are not wired to the switch, we cannot use a dimmable smart switch to be able to manually dim the smart lightbulbs from the switch. We can turn them on/off at the switch, but not dim them. We can only dim them from the app?

Also, will the smart switch (non dimmable or dimmable) only work with a neutral wire available at the plate? We don't have that unfortunately (old house).

@ChloeS 

For both of your questions, you are correct.

The switch can not manually dim the bulb, you would use the Kasa app or have Google or Alexa control the dim.