Simul rules summary:- Players state intentions. Players roll dice simultaneously. All players progress if ANY player meets or beats target roll. Otherwise players suffer setbacks, give ground, take losses or progress with consequences.
Using real dice and a tabletop computer-aid (eg tablet browser) all players throw dice together after saying "Ready, steady, roll!"
Simultaneous resolution of action
count the people on our side (Us),
count the opposition (Them),
enter the number of active players,
Us-vs-Them app says which dice to roll.
If new to tabletop Role-Playing Games (RPG), try playing Dungeons and Dragons, Star Wars Roleplaying Game, or Traveller role-playing game.