niagara crowd movement

I’m trying to follow the niagara crowd example for using niagara to make lots of characters
https://www.youtube.com/watch?v=CqXKSyAPWZY&t=2s. It explains a couple things like animation and kills but it doesn’t explain how he controls the crowd. He says he makes certain characters follow others but doesn’t say how to do any of that. I can’t find any videos or information anywhere on how to do that. I know you can’t use arrays as user parameters so I cant send niagara the information through blueprint on where to send each character. Does anyone know of a tutorial for moving individual particles through blueprint or have any idea how to do that? I would like to try to use niagara for that but I can’t find any info for how he’s doing the things he’s doing in the video.