How to Set Up 3 Variation Options on an ASIN?

I have a particular ASIN where it would be helpful to have 3 variation options, such as Size, Style, and Color. I only see the option for SizeStyle on the flat file. I can’t find any variation value for 3 variation options. I know it’s possible because several of my competitors have their listings set up with 3 variation options. One example is ASIN B07QMTPVC9.

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Curious if anyone can offer some insight into how to do this?