1. Set Pieces are referred to free kicks, corners and penalty kicks which will let you choose the players to be CAPTAIN, FREE KICK SHOOTER, FREE KICK PASSER, PENALTY KICKER, CORNER KICKER.
2. If you are not sure which player is suitable for a particular role such as free kicks, you can long tap the "Set Pieces" button to display all player's finishing/passing/captain attribute.
For example, you can choose the player who masters the skill of free kick with the highest finishing as suitable for the role.