Cannot find COMPATIBLE feature

I want to filter product depending on compatibility. I can see following segemnet in documentation

“COMPATIBLE

Make sure all selected product parts will work properly. The compatible feature works based on attributes values. For example: In STEP 1 – CPU, customers select a CPU with the attribute “Socket” has its value as “LGA 1151”, then in STEP 2 – Mainboard he will find only mainboards which have the socket LGA 1151 (this attribute value must be added to products)”

I have added attribute to my products but I cannot see an option where I can enable the COMPATIBLE. Could you please help me to sort this out?