Spread the mat out on the floor. It will be very, very long, which will make it clear to the children that there is about to be some sort of interesting or exciting presentation. You may even need to clear space on the floor, which adds to the suspense.
Line up the unit bead, the ten bar, the hundred chain and the thousand chain on the mat. They should all be parallel to each other. While the unit bead and the ten bar will be familiar to most students, the hundred and thousand chains will be far more impressive.
Count the chains together. As you do so, assign the number cards every ten beads. This will not only help you keep track, but it will help the children see how many tens go into one hundred and one thousand.
Allow the children to continue to interact with the lesson individually. If the lesson has disrupted the natural order in the classroom, you may wish to have children take turns with the chains over the course of a single day. Some will wish to count them repeatedly, while others may do little with them other than look at the relative lengths. Most will count the beads, but some may not wish to use the number cards. If they do not, that is fine. If the lesson can be used without disrupting the classroom space, then you can allow children to lay it out whenever they wish. However, remember that the impressive lengths of the longer chains may cause some disruption in the classroom whenever the lesson is used.