How can i revive or change my units on the field? It is easy!
There are recovery zones. You can see the plus icon on the minimap at the top right.
Approach the Supply Quartermaster and interact (F).
Click the Choose Unit and that's it. You can easily change or revive your units.
this did not help, i need to know how to heal my units when im not in a match
You can replace your lost troops by recruiting more from cities, or by healing injured soldiers in medical tents and cities.
You must recruit more reserve troops to heal your current units. While near a city, you can choose “Heal Units”. You can also construct a Medical Tent out in the wilderness, which you and your allies can use to heal injured soldiers.