How can I make sure to heal all wounded troops?

Your capacity to hold "x" amount of wounded troops is based on:

1) How many hospitals you have (you can have a total of 8)

2) How much you have upgraded each hospital (each level increases your wounded capacity by roughly 750 troops)

The more hospitals and the higher the levels for your hospitals, the more wounded troops you can hold if your army is completely wiped out by an enemy.

Typically I recommend 8 hospitals that are at the level of your HQ (so if your HQ is level 20, I recommend 8 hospitals, each being at level 20). This will maximize wounded troop capacity while also minimizing the amount of troops you lose PERMANENTLY. What this means is if my wounded capacity (You can check this stat by accessing your parade building) is 100,000 but my army is 150,000, and an enemy wipes out all 150,000 of my troops, 100,000 will be wounded and the other 50,000 will be permanently lost.

To heal wounded troops, click on one of your hospitals and just click "heal". Although the higher tier the troops, the more resources it will cost to heal all of them. The first couple tiers will cost just plastic and paint, but as you progress to higher tier troops (tier 6/7), the more precious metal resources will need to be utilized