The basic movement with one club is shown in the animation below. The club
is thrown by juggler A (who is invisible but we have to imagine him on the left),
and is then caught by juggler B (on the right of the animation) who replaces
it during the movement in A's hand.
If A throws a club with their right hand, then it will be caught by the right hand of B, who replaces it in the left hand of A. B has no influence on the trajectory of the club.
B can then try and do the movement while A is juggling normally, by alternating the right and the left hands.
The main purpose is then for B to catch each club in this way; every club has to have been in their hands. For that, it is necessary that A remains cool and juggles as slowly as possible. Once the pattern is stable, A can start watching elsewhere since B places each club into their hands.