Moving Units

hi I declared war on a C3 and when I click on my unit and then click where I want it to go...the arrow points somewhere else, like way far away outside the county I've declared war on.
Can someone help me with this or is there another option for moving units or am I doing it wrong thanks thanks!

Try clicking on a target, like a county, fort or factory. I haven't been in a war for a while so that is the best help I can give you.