The order of your Email Filters or Rules define which how your email is organized within your folders. When a message arrives at your inbox, the rules you have created will monitor the message to see if the message matches any of the conditions you specified. Only one rule can be followed at a time, so you must establish an order if you have multiple rules to perform.
If you have multiple rules that relate to each other, the order becomes critical. The rules that appear first on your Rules Options page are followed FIRST. You can change the order in which the rules run by clicking the up or down arrows in the Move column. The ones that appear first, or higher on the list, run before those below.