Parent child list

Hello,
I want to send my products for FBA but could not see FBA option under manage inventory. Seller centre says "Your listing is a variation parent.

• The parent product is a non-buyable product used to relate child products.
• The Amazon catalogue uses the parent product to establish relationships between the child products."
  I am not sure what this means? How can I do my parent pruduct to child? Can anyone help advise what I need to do about my listing to make sure it can be FBA? I made my list without excel just adding one by one.

Please any advice would be appreciated.
Thanks in advance!