How Herald of ice/thunder scale damage?

Guys, if i use herald of ice/thunder on flame totem, do totem damage, proj damage, spell damage increase heralds damage? or they just scale with ice/light damage?

In general how can i scale the add x-x damage of heralds? THey act like a added chaos support gem?

added damage from lightning/ice herald acts just like any other source of added damage. It adds damage to your skill multiplied by skill´s damage effectivness. Then it becomes part of your base damage thus will be increased by all applicable modifiers