Most of the sambas that I teach come from the Beatlife book that I have mentioned before. I start with a fairly easy set of rhythms, at a moderate tempo, and work up to more complex ones as time goes on.
Once the children have become better at keeping a steady tempo, and listening to each other, and watching the leader (usually me!) and following signals (usually mine!), we are ready to embark upon a bit of creativity.
I set each group of instrumentalists the task of creating their own group rhythm, using a phrase to help them remember it. If you need to link in to a topic, this is your opportunity!
WORDS OF WARNING: To begin with I separate them from the instruments, and get them to try out their rhythms by just clapping them. Then I let them practice their rhythms on the instruments WITHOUT USING BEATERS. The children will moan like mad, but trust me – once they start using beaters, the noise levels make any further group work an impossibility!
Your job now is to visit each group in turn and make sure that they are “on task” and coming up with a rhythm, and also that the rhythm is not too long, not too complicated, and fits with four beats in the bar.
Once each group has their rhythm, they can take up their beaters and play it to the whole class. Then you can start assembling them into a samba, adding and intro, breaks and ending.