There are two ways of using the beads, the first is once every pace or ten paces (or other unit you are counting), or by distance – once you know how many paces represent a given distance. Here is an explanation of how to use them I found online:
“Now that you have your pace count down you can start to use the pacer beads. Now take and attach the pacer beads to either your clothing or field harness, and pull all of the beads either up or down (your preference but do it the same way all the time). At nighttime you will not usually be able to tell how far you have gone. And if you are using a map and a compass and are trying to get to a certain point then it is important to know how far you have traveled.
So find the place you need to get to (in meters), get your compass heading and start moving. Every time you reach 100 meters (by counting your steps) you pull one of the beads from the bottom set of nine beads up (or down) and start your pace count again. After you have all of the nine bottom beads pulled up you will have traveled 900 meters, count your next 100 meters.
Now this time you pull up (or down) one of the four beads that are in the top section, these beads represent 1000 meters traveled. You now pull down the nine beads in the bottom section and start your count again, pulling one bead in the bottom up each time you have gone 100 meters. Each time you get all nine beads pulled up you go another 100 meters and pull one of the top beads up. This will allow you to keep track of 5000 meters that you have traveled.”