As EpsiloN you will want to run the entity both on the server and client. And every once in a while you let server update it if needed.
So first off don't forget to set dplay_localfunction to either 1 or 2 somewhere in your script (actions run on clients too), you probably don't but just to be safe. I once forgot this and was searching for bugs like a headless chicken.
white(connection != 0 && my.client_id < 0) wait(1);
as your first line in the action. Or it was white(connection != 0 && my.client_id == 0) wait(1); .
Than determine what part of the code you want to run on the server only, and what on both the server and client.
And add the lines to actually send the data from server to client (send_skill, ent_sendnow, whatever you prefer).
Also a tip I once saw on this forum was to set dplay_entrate to a very high number (high dplay_entrate means a long time between updates) and use send_skill and/or ent_sendnow, so you have more control. (allowing for better interpolation, optimizing bps etc.)