Let me see if I can help, I referee hockey..
A team can never have less than 3 players on the ice, not counting the goalie
so that would be 4 total players on the ice as minimum...
The player who gets the penalty goes to the box but his penalty time does not start until the first penalty is up...
Say for example:
Player 1 gets a penalty at 5:30 He is out at 7:30
Player 2 gets a penalty at 6:00 He is out at 8:00
Player 3 gets a penalty at 6:30 His penalty starts at 7:30, when the first player's penalty is up and he gets out at 9:30..
Now say that a PP goal gets scored at 6:45 the first player would come out of the box and player 3's penalty would start then at 6:45...
Hope this helps, it can be confusing...