How do you level up the attackers under your main hero.
if you mean the troops, you need to build a barracks to level troops. details here https://sites.google.com/site/empiresandpuzzlesrpgwiki/intro/base/barracks
I’d recommend converting an extra forge rather than something useful.
I believe they have fixed it now so that iron storages cannot be used as Barracks. An extra Forge really is the best building to use.
Thanks very much for your information i greatly appreciate it