Cudy's VPN configuration

HI.
I need to configure a Cudy router LT500. I created a public ZeroTier network. How should I set the router, with master or slave protocol? If with slave protocol, which gateway should be set?

My CUDY LT500 works well for a camera network using an inexpensive Mint SIM card. I am a newbie to all this, but here is my configuration: