There should be a line in the bottom corner. It should have a 0 on one end and another number on the other end depending on the scale. It should be in kilometers, meters, or miles. Take a piece of paper, put the edge of the paper on the 0 and mark the number on the end. After you are done with that, put the 0 on your starting place then put the other end near your second place, if the other number doesn't reach mark it on the map and place the 0 there. Repeat until you reach your destination.
Hopefully this helps!!! :)
P.S. sorry that it is so wordy...lol