I’ve just added this to the samba page:

Set up a steady vocal counting to 4: 1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4

allocate a number to each section, and see if they can maintain the pulse. It’s probably best to work up to using instruments step-by-step: I ALWAYS go “say, clap, play”,  except when I forget, and when I do forget I always regret it. I generally arrange the samba groups in a square or horseshoe when I am teaching, so the obvious thing is to number off the groups in order round the room.

To increase the challenge, change the order.

To increase the challenge further, add rhythms; eg 1,   2 – 2,   3-3-3,  4, (or 4444)  while keeping the pulse.