This is how it works. The parent draws numbered squares in a row—three or five or however many the parent thinks makes sense and in the last square puts a picture or words that tell the child what will happen. This is a Duration Chart and each square does not symbolize a discrete turn or a set amount of time but rather the parent crosses out one numbered square at a time as fast or as slow as the parent feels is appropriate. Doing it this way is very useful!
Choosing the length of time for each interval of the duration, gives the parent a lot of room for using good judgment. Suppose your child never stays at the dinner table but instead, runs around the room and zooms in to take a bite of food from time to time. When the Duration Chart is first introduced, with the aim of helping your child to sit for dinnertime, you might want to cross off the numbers very quickly and then provide the reward pictured in the last square, and send him or her off to run around as usual. That is it for that night. Gradually, over many dinners, you will extend the time that you take to cross off the numbers. Your child will be waiting now for you to cross off the numbers before flying away. Gradually, your child will stay for longer and longer until he or she stays for the whole dinner. If, on a particular day, your child is not having an easy time sitting (perhaps there is a different person at the dinner table or a food that your child does not like to smell or just a hard day for no discernible reason) then you cross off those numbers faster again and don’t require that your child stay for the whole meal. The child can be the one to cross off the numbers but you choose when he or she does it. The duration of time that this chart represents is up to the parent, not the child (don’t give that away!) and the power of the method is in the parents sense of how long is the right amount of time for each interval on the chart-the reasonable amount of time from the child's perspective but from the child's perspective, clearly staying in control of the Chart.
Now, what is interesting is that for many children, the idea of a Duration Chart can be taught very quickly and the child begins to use this visual support to stay calm while doing activities that were always upsetting before. It is like magic.
More Tips: 1) Use Charts that you draw with paper and pen rather than computer generated charts like I have shown you here. It works just as well for most children and it is fast enough that you will do it. 2) Teach easier things before harder things. If you are trying to help your child learn to leave the computer calmly, but this is very hard, teach your child to leave other less desirable activities using the duration chart first. 3) If your child cannot do a task, the chart won't help. Consider whether the task needs to be taught in a more simple form, demonstrated, or taught when the child is older.