Remote Desktop using sidecar

I started using sidecar. Nice feature but I could not find out how to keep using my Mac as a primary desktop. Activating airplay it moves the desktop to the ipad unlike all videos I watched suggested.

One more thing. Even checking off settings the airplay box with the triangle does not appear on my desktop, hence I cannot control the features of sidecar like resolution etc.

How can I fix that? Thanks Walter