How to Play "Once More..."

About Once More..., from BoardGameGeek:

Once more is a quick, solo wargame where you will take your squadron of four biplane fighters out on missions to support the troops at the front or clear the way for them to move forward. You will need to make decisions about when you attack and when to coordinate your fighters against an enemy of aerial fighters and ground troops. Be careful, resources are scarce and once one of your planes is shot down, there are no reinforcements to fill the ranks. -description from the designer