Register Players and Coaches for the National team
On the list of players will appear only the ones that were previously assigned as national team players. So, before assigning them to the match, they have to be marked as national team players.
In order to do so:
Open a player card
Press the Options button > hit the New registration (National team) button.
Inspect the National team registration details and hit the 💾 Save button
Once you have done that, the player is marked as a national team player and it is possible to assign him to the match.
If a player, for some reason, can no longer play for a national team, he can be deleted the same way he was added.
The coaches are assigned the same way.