Look at some games when you have won with your preferred formation, and use the possession number as a guide. If you are a bit under, give possession bonus.
You're winning and have another match, try condition bonus; or if you get early goal condition and wait for more attack later.
Opponent has stronger attack than your defence and you're trying to counter, or your ahead of a stronger opponent, try defence.
Even balance but you're playing attacking strategy, try attack bonus.
I use them all, mostly attack and condition, gets me late goals sometimes when I use condition for middle game.
There are more threads discussing arrows in general discussion, a big one recently.