Hearts of Iron 4 has you assign infantry and armor divisions to a general, and each general to a front. This front is a line that you literally draw on the map, usually along a border you want to invade or defend. When fighting breaks out, you draw a second line in front of the first representing the point to which you wish to advance and capture. Your forces will automatically move in a united front, engaging the enemy in several provinces at once. Smaller strike forces can be held back under a sub-commander, and deployed to specific areas along your advance where fighting is thickest.