This is a pretty snowflake top pattern I made for the December "let it snow" challenge. It includes sizes small, medium, and large. It has lots of helpful progress pictures ad well as some amazing tips for making granny squares I use.
Disclaimer: I would not recommend this pattern to beginners, and also recommend that you know how to make and join granny squares already. I include clear step-by-step instructions, but not beginner tutorial level detail.