I create my own screens as I am the newbie screen printer. Even if someone else designs an image and separations, it will be my responsibility to print the separations on individual screens.
Until my skill level with Illustrator gets good enough to understand more of the videos out there, my process for color separation is built on what works to get the job done. Objects are grouped. Then in the Layers panel the top layer shows all the groups. I look at each color within the grouped objects, then assign similar colors to their own layer. Each layer gets printed on clear film.
My homemade registration marks have to be placed on each layer. Fortunately they can be assigned a specific location on the artboard to make alignment easier.
Thank you for your help.
In that case the registration swatch might not help you a lot and you need to assign the color that you have on that layer. Also put the marks on each layer.