The 'Who Is Playing' feature is a very important tool.  Not only does it let our loggers know who did (and didn't) play in a match, but it helps track such things as substitute athletes and temporary jersey changes without affecting the permanent stats record.

When you upload your game, you'll be presented with a 'Who played in the game?' box.  Simply click 'Add Athlete' to get started.

When you do, the list of active athletes currently on your roster (or your opponent's roster) will present itself.  Put a check mark in the box to the left of each player who played in the game, and press the 'Add Athlete' button again to add them to the list of participating players.

After your roster list of active players for the game populates, if you wish to add a player/jersey not presently listed on your active roster, click on 'Add Athlete Not On Roster' to add them:

Enter in the athlete info and 'save' it:

With your roster now assembled (you can even designate starters), continue on to your upload!

IF ONE OF YOUR ATHLETES IS WEARING ANOTHER JERSEY NUMBER IN A GAME, load your FULL roster active for the game into the 'who is playing' list as normal, and click into the 'Jersey' column for the athlete.  Change the entry to the new jersey number and 'close' the box. 

(Again, please add your FULL roster, as the entries in the 'who is playing' box will overwrite whatever default roster you have in place in your account.)

This will not only allow the player to be tagged with their new number, but all the athlete's stats for the game will track along with those already accumulated with their 'usual' / 'original' jersey number:

TO ADD 'WHO IS PLAYING' INFO AFTER A GAME HAS BEEN UPLOADED OR LOGGED, simply click on the 'actions' dropdown (the small box with the upside down triangle in it) to the far right of the playlist title and select the 'lineup' option there: