Please see my attempt to explain the routing in a simple way: Zerotier router setup not working - #4 by AndrewZ
A few advices:
- do not use 10.x.x.x in Managed IPs, there is a potential overlap with the mobile broadband IP assignments
- do not use 192.168.x.x in Managed IPs, there is a potential overlap with LAN address space
- use smaller subnet for Managed IPs, i.e. something like 172.28.4.0/24 and assign all the addresses manually/statically
Assuming you have a router or a PC acting as a router, create a managed route like this:
192.168.20.0/24 via 172.28.4.20
where 192.168.20.0/24 is a LAN behind the router and 172.28.4.20 is a ZT assigned IP