You can support fellow Order members economically or militarily by sending reinforcements or carts of resources to their Towns. You can exchange messages with all members of your Order, so it’s easy to find out if anybody needs your help. All of these actions are available in the Order menu, Membership tab.

Tap the "Action" button next to the selected player and perform one of the commands:

The higher the level of the Port, the faster carts of resources will move.