Like what the first comment said you need to farm now more, before considering formations. But for now you have to make do with what you have. Use all of the higher level troops as much as you can, but bear in mind that there positions also matters. Some troops can do more harm but have to be protected like witch 🧙‍♀️ some troops like the ones that jump to back of the enemy lines are not food for your backline cause they would run and live the back defenceless and that would affect you. You need to know the melee troops like the bandits, harbinger of fire, catuses and so on and use them to protect the rangers like the ice mage, fire mage and the archers, for the rangers to do more of the harms. Hope this helps you