First layout your sweatshirt flat and zip it up if it does.
Fold in the sleeves. Its is ok if its not perfect, because i think it's comfier if its not.
Roll the sweatshirt up starting from the bottom, to about where the hood starts (You might have to fold in the edges a bit)
Last step. Take your sweater roll and stuff the whole roll into the hood. You might have to unbump it a little, but what ever.