Outdoor Cam w/Cam Plus & microSD card

I am using the Outdoor Cams inside since they are wireless and I have a toddler and a baby on the way. I have a microSD card in each camera and the base, plus I have Cam Plus.

Here is my question. Once the camera starts recording, where are my videos stored since I have a microSD card in the cameras, the base, and I have Cam Plus?

I’m trying to figure out if my microSD cards are being used or not.