Help intall grist vpn

I have the following configuration:
vps with public IP on which I installed nginx (configured in reverse proxy) and a vpn, zerotier.
A server PC at home with zerotier and grist-omnibus (or even core) installed in docker.
My problem is that I can’t configure the environment parameters correctly to view from the internet by pointing to the nginx the grist server.
Can you help me?