Getting npc to run command on player
what i want to do is get the npc to run the command on the player because usually the players have to do is type /at in chat for them to join a arena but instead if they can press e on the npc and it runs the command for them i dont know how i have to put it out in the config though for the npc to run the command as if it was the player typing it 
player.SendConsoleCommand iknow its something like that is there some one who could maybe help me ? thanks
check the arena plugin you are using see if they offer a console command to place user in the arena.