Knitting Pattern Help

Hi, I’ve been knitting for a year so I consider myself a beginner. I bought a beginner pattern for a hat today that I’m struggling to understand. It says the brim is knit flat and joined later when changing needle sized. I know brimmed flat means not in the round, but I’m confused as to how this transitions to the hat body. Here is the pattern:

Setup 124 stitches in largr needle
Setup rows - switch to smaller needle, 6 rows of knitting

Brim Pattern:
Rows 1,3,5,8,10: K2,k2tog,k to last st, sl1
Rows 2,4,7,9,11: p2, p2tog, p to last st, sl1
Row 6: P2, p2tog, p to last st, sl1
Row 12: k2, k2tog, K to last st, sl1
Repeat twice

Had Body Setup: Using the knitted-on cast-on method, CO 13 sts, sl 1st st on right needl to left needle, being careful not to twist, k2tog, place marker, knit two rounds. Change to larger needle, Work one round in 1x1 rib.

My questions:
When I transition from the brim to the Hat, is the knitted-on cast on method adding 13 stitches to my brim? Or am I supposed to cast off and start a new cast on for the hat body?

I’m used to patterns stating when to join in the round and this doesn’t specifically state when. Am I joining in the round after the k2tog?

Thanks all!

Can you tell us the name of the pattern and post a link if possible? It helps if we can see a picture even on purchased patterns.

It sounds like this may be a sun hat with kind of a flared brim? And the 13 cast on stitches seem like they might be a gap in the brim which probably sits at the back of the head. Is that correct?

This is the way I see it- No, don’t cast off or cut the yarn unless it tells you, too. When you turn your work after the brim so the stitches are on the left needle cast on the 13 stitches using the knitted cast on. When you slip one stitch to the other needle and k2tog that is so it’s easier to join without a gap. Then you will continue in the round. Does that help? I can picture it in my head, but not sure I explained it well.