These should help and all are free
crowd maker:
https://web.tiscali.it/maya_tutorial/
brainbugz:
https://www.kolve.com/mp_brainbugz/brainbugz.htm
and my weak unfinished emulation at trying to do similar things as the systems above using craig reynolds 'boids' techniques:
https://www.flash-fx.net/3D/tools/bFlocking/
Si