From FastScout Web - https://fastscout.fastmodelsports.com/ - find the play you'd like to see via the mobile app and select the mobile icon on the left. You can also select Mobile Access to select multiple plays at once.
If you select Mobile Access, check the plays you want to add/remove and then press Manage Access.
Whether you're enabling/disabling mobile access for 1 play or multiple, you'll see a list of all users in your account. For most accounts, you will only have coaches and players. You can select the check next to the header to quickly check/uncheck all users under that category. Once done, select Save in the top right corner.