Instantiation of created objects for all players

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This is how I want the system to work: 1 user will create 3D sketches using a custom volumetric line renderer (works the same as unity's built-in line renderer), once the sketch is done I want to be able to render (Instantiate) this sketch across all the users in the room. I have been looking into RPCs to try and do this but am not sure where to start.

Any help or resources will be appreciated. Thanks.