Anael a Round Robin can be done two ways.
1. you make the centre block and then it is sent to the next participant
2. you make the centre block and add the rows yourself.
Either way you follow a "recipe" ie first border may have to consist of squares and measure no more than 4 inches, second border may have to incorporate triangles and measure no more than ??? or you may have to add an applique border
I have participated in one and I vowed never never again, the whining and complaining was incredible, and the workmanship of a few participants left nothing to the imagination.
I have a quilt in my lounge room that was sort of made as a Round Robin, I made the centre block and DD decided on what border had to be added. She said "Trust me Mum" so many times when I would question her choices that that is what I named the quilt
There are a few book available on this type of quilt, they can be a lot of fun or a disaster, just depends on who you do it with
I have spent the day sorting out my project boxes and have 11 ufo's darn I was trying to keep it under 10, but I only have 6 rows to add to my Scrappy Stars and borders and it is finished so I just might get to that magic number soon