Sometimes it’s hard to tell how far away another unit is. When the squares aren’t outlined, what’s the best way to verify distance. Also when selecting an attack for a Warrior is it 3 squares max including the target or 3 squares between the targets? I thought it was 3 squares including the target but I think I recently died when the target was on the 4th square. Which goes back to the first question because I didn’t have a way to validate.
When you select the Attack action on a unit, all the tiles that are in range of the attack will be highlighted in grey, that’s the best way to tell if attack will work right away. That will also help with your second question: if the opponent is on a greyed out square, you know they are in range.
But, to answer it directly: distance in any context is always measured from the center of the start tile (in this example, your unit’s tile) to the center of the end tile (your opponent). If you want to count whole tiles, don’t include the start tile (do include the final tile). Works out the same.