Stock variations

I would like to add my stock on PPOM. But i can’t do that?

I have multiple options for my products using PPOM like size and color.
but only can using stock for one of them? not combined sized and colors?

Example:
Red size 1 is on stock
Red size 2 is out of stock
Red size 3 is on stock

Blue size 1 is out of stock
Blue size 2 is on stock
Blue size 3 is on stock

Pink size 1 is out of stock
Pink size 2 is out of stock
Pink size 3 is out of stock

Look at my page on https://www.plotterspecial.nl/product/siser-p-s-film-easyweed/

Anybody can help me with this?

The page I need help with: [log in to see the link]