After a game is complete, team admins are able to submit individual player stats both through the web and through the app only if the league has enabled this feature.
From the App
Press on Events tab and click into an event
Scroll down and click on League Statistics
Enter in your stats for your players and click Save
From the Web
Select your team in the top right Dropdown
Click Schedules > Schedule in the left menu bar
Filter for your Past events
In the Actions column click Stats
Enter in your player statistics and click Save