Sort rules are automatically applied to incoming emails in the order you assign to them.
If you create more rules associated with the same email address (subject, word, etc.), Inbox.com applies the rule which has higher priority than the other rules.
This order may be changed anytime you want.
To change a sort rule order:
Select the "Settings" tab and "Sort rules" option in the left menu.
Click on the blue buttons with white arrows to move a sort rule up (to add priority) or down (to lower its priority).