01) Access the Control Panel

02) After login click on Catalog >> Options

03) In the box Variants when entering / editing select checkbox Track Inventory

04) After clicking the Insert / Update button

05) After configuring inventory tracking, go to Catalog >> Catagories / Products or Suppliers Products

Check out the tutorial how to enter attributes and variations in the product

06) After entering / editing attributes and variations in the product click on Options >> Stock

07) You can enter the desired quantity by attributes and variations