Plutonium

Ive tried and failed to set up modded game with my friend. We tried to play via putonium and bgamert5 launcher. Ive read about way to play mods by setting up bgamert5 dedicated server but we have same error about missing file popping up when trying to launch dedicated server.
When I try to launch mods on plutonium it freezes and closes up on loading screen.
Plz help us we want to play mods so bad ;<<<<<