To upgrade your troops, please follow these steps:

-Tap on the barracks of the unit you wish to upgrade.
-Press the “Training” icon.
-Scroll through the troop types until you find the unit you want to upgrade.
-Once you find it, tap the green arrow icon below the unit, if available.
-Select the quantity you wish to upgrade, then tap “Start Training” to complete the process.

Important Notes:
-Only the units currently inside the city will be upgraded; units outside the city will not be upgraded.
-The selected unit will be automatically upgraded to the highest available level of the same type.