Simplest way to run functions both ways on LAN Host and Client

Hi,

I'm fighting with UNET to achieve something that seems simple, at first >_<

I want to create an application which displays the same thing on two computers, one is a LAN Host, so is recognized as a Client and a Server, and the second is a Client only.
Both applications has to be synchronized, when doing something on one, the other must react the same way.

I can send RPC call from the host to the client without problem, but impossible to get Commands to be sent from the client to the host. I'm stuck on Authority problems but can't find any clear/helpful answer on the web.

Where should I find the simplest atomic example project of such a setup ? Or could someone share some sample code or advices on how to do this please ?