this is an old trend which i've seen happen before but not recently, these trends were kinda nostalgic so anyway how do you join the chain one person starts it before the next person remixes takes a screenshot of the entire page and then adds their character in front of it
you wouldn't see it if it was in instructions so it's here the examples https://scratch.mit.edu/projects/92691485/ https://scratch.mit.edu/projects/2669374 https://scratch.mit.edu/projects/92580246/