@William Walace (INT1)
On the menu bar at the bottom of your window, where you find Hero Information, Construction, etc, at the far right end of that bar is a banner with either a snowflake, green leaf, or crossed bones on it. That is the icon that opens the "send resources" function.
Say you want to send iron to the High Kingdom. On the row that says High Kingdom, click on "Send Resources" red button. if you are in Ice Kingdom when you do this, then just look down the list of resources to the icon that looks like a bar of iron. Slide the counter to the right, and you will see on the left what you have in Ice Mts, on the right what you have in High K, and how it changes as you slide that counter. A little box in the middle shows you exactly how much iron you are loading to send.
When you have the right amount, click the "Send" button bottom right of the window. It takes 2 hours by normal transport, or you can speed it with gems.
Units and unit boosters can be shipped the same way, but not heroes.