How do I replace the earpads and the cushion?

How do I replace the earpads and the cushion?
I have this headphones sitting in my closet since a very long time and over the years the pillow cushion and the sponge (ear pads) have either got cut or the leather on the pillow cushion is coming off. is there a manual for me to replace it on my own?

ANSWERS:

"You can buy new ear pads from AliExpress. Do you know how to replace these ear pads or do you need instruction on that too?

aliexpress/item/Replace-..."