Organizing random items on amazon

I order shipments of a variety of random items and sell them on amazon; there is really no organizing it so what I do now is put them in big black totes (27g ones) based on category. When I list my items on ebay I put the location of the item in the notes (assign each box a sku) but on amazon I am not aware of having that option. Keep in mind Im listing products with already existing product pages. Now as I am scaling up I am having a hard time keeping track of the items Im listing on amazon and need help find a new inventory system or anything simple like how I keep track of my Ebay items. Please let me know if any of yall have any advice thank you.