Tethered and overlays in LR CC

Hi there 🙂

I've got a question about a situation I didn't have before.

Tomorrow I've got to make some photobooth-like pictures.

OK - I'm planning to do that tethered with LR CC.

Now my problems:
I don't want to make every photograph from LR, but from the camera but
LR should automatically do some action and should ad an overlay (a frame with some words about the event)

So as result - I'm using the camera and LR is doing the rest by itself.

Is that possible or do I have to use PS ?

I can't by some  photobooth-software instead. The club i'm in can't pay that in addition.
So I'd urgently need some tutorials, tipps and tricks to manege that tomorrow.

Thanks
Mathias