How do I use the Reserve Skill?
 

So I finally got the reserve skill in the Green tree. How do I use it? There doesn't seem to be a button anywhere to use it :/

Do I need troops of the same type in my reserve slot? Do I need to wait till turn 8?

You can only get more troops in battle if you have enough leadership for them.
So expl you start battle with 100 griffins and 50 in reserve, then 10 griffins die at 6 turn. In 8 turn you`ll get option to import 10 griffins from your reserve slot.
When you CANT use it :
- ofc you cant import troops in full stack , in case you have 100/100 griffins and in 8th turn you cant import more, since you have no leadership for them
- you lose 10 troop of some kind , and in reserve you have some other units. You cant import from reserve other kind of unit then those you lost in battle.

a horrible option for a no loss battle :D

yes you need the same type. They forgot to write it down in description of skill in skiltree:confused:

Seems to be obvious to me since the idea is to reinforce troops you already have on the field. Can't add Apples to Oranges.