Well medieval Serbian army wouldnt be like that at all...
Kings guard and noble cavalry would be classic HC with heavy mail+partial scale armor, mounted on a war horse with light scale protection. Other then that there is no other HC. Infantry is combination of heavy inf (more with spears and axes then with swords), medium infantry with shields n spears and light skirmish infantry. Most of the archers would be light foot units specialized in woods combat and ambushing. Some of light cavalry as HC and scouts. Except kings guard, most of the army is armed with axes n maces for melee fights.
Army is kinda mix of ERE and Hungary/HRE styles. Same goes for armor and arms. Hopes this helps