Charges are resolved one at a time now. You roll each units charge roll before you move on to the next charge. An example would be if you had 2 chariots charging a a big lizard and a unit of horse charging a different unit. You would declare both charges on the lizard and get combat response before you moved on to the charge on the different unit. once all resolution has been determined, you would roll both chariot charges and move them before you rolled the charge for the horse. Hope that helps.