Confusion with knitting pattern

Hi, I’m Kellie. My mom taught me to knit when I was young but in the past 5 years I’ve picked up my needles again. I’m confused by this pattern which appears to suggest different size pins for different size of garment. Am I correct? I’ve never seen this before.

Welcome to KnittingHelp!
I’ve never seen this either (and I’ve seen a lot of patterns). Does the pattern give gauges for the various sizes? And what yarn does it suggest?
What is the name of the pattern and designer?