Changing pattern from flat to circular

I have a pattern that I would like to change from flat knitting to circular knitting, and I have NO idea how to do it. Can anyone help?

Here is the link.

It looks like you knit the band back and forth the narrow way and then you can pick up stitches all around the top edge and knit the rest in the round.

A few weeks ago I taught myself slip-stitch mosaic knitting to make a booga bag (in the round). So yes, you can definitely convert that hat to circulars. It’s too late tonight for me to figure it out, but if you can wait until tomorrow, I’ll give a more detailed description. I put two of my kids and four daycare kids on the bus at 8:45am (Eastern time), so I’ll try to start soon after that! PM me if you are interested. If you’ve gotten so excited that you figured it out, let me know so I’ll save myself some work!

There are a couple of problems with converting the pattern to the round: on flat knitting, two rows are worked identically, which is why the design has “stripes” of two stitches high and wide. On circular knitting, you’d have to slip stitches two rows to get the exact design. This didn’t work well for me – my slipped stitches were huge and ugly. So, I cheated and alternated colors every row, but that meant slipping more than 3 stitches at a time in a row (not recommended, but since my bag was felted it didn’t matter) On a hat, it’s a different story.
I’m going to post pictures of my bag so you can visualize what I mean.
Meanwhile, I designed a new chart, but before giving you all the directions, I want to make sure you like it. Other options would be to make the design almost identical to the one pictured (but with skinnier “stripes”) but then the band would only be half as tall (11 rows instead of 22) You’d just have to make the solid part longer.
Let me know if you like the one I drew, and if so I’ll continue on…

I thought I did that right but apparently not! Here’s the messy chart:

Here’s the pattern using the spiral chart I posted.
The slip-stitching can be a little tight, so knit loosely or use a bigger needle size for the brim band of the hat.
I’ve never written a pattern before, so let me know if you have any problems or questions.
Just leave the unused color hanging off the back. When changing colors, bring the new color up from behind the old one so that they wrap around each other to prevent a hole.
For Rounds 3 through 19, all odd rows will be worked using the dark color (D) and all odd rows will be worked using the light color (L)

With light color, cast on 81; join in a circle.
Rnd1: Knit
Rnd2: Knit
Rnd 3: (D) [sl 1, k8] around
Rnd4: (L) [k1, sl 1, k6, sl 1] around
Rnd5: (D) [sl 1, k1, sl 1, k4, sl1, k1] around
Rnd6: (L) [k1, sl 1, k1, sl 1, k2, sl 1, k1, sl 1] around
Rnd7: (D) [sl 1, k1, sl 1, k2, sl 1, k1, sl 1, k1] around
Rnd8: (L) [k1, sl 1, k4, sl 1, k1, sl 1] around
Rnd9: (D) [sl 1, k6, sl 1, k1] around
Rnd10:(L) [k8, sl 1] around
Rnd11:(D) knit around
Rnd12:(L) [k8, sl 1] around
Rnd 13:(D) [sl 1, k6, sl 1, k1] around
Rnd 14:(L) [k1, sl 1, k4, sl 1, k1, sl 1] around
Rnd15:(D) [sl 1, k1, sl 1, k2, sl 1, k1, sl 1, k1] around
Rnd 16:(L) [k1, sl 1, k1, sl 1, k2, sl 1, k1, sl 1] around
Rnd 17:(D) [sl 1, k1, sl 1, k4, sl 1, k1] around
Rnd 18: (L) [k1, sl 1, k6, sl 1 around
Rnd 19:(D) [sl 1, k8] around
Rnd 20: With light color, knit around
Rnd 21: With light color, knit around

Now you can cut the light color and use the dark from now on.
Rnd22: Increase one stitch in the beginning of the round, then knit around (you should now have 82 stitches)
Rnds 23-42: knit
Round43: [k18, k2tog] around (77 sts)
Rnd 44: k
Rnd 45: k
Rnd 46: k
Rnd 47: [k 9, k2tog] around (70 sts)
Rnd 48: k
Rnd 49: [k9, k2tog] around (63 sts)
Rnd50: k
Rnd 51: [k9, k2tog] around (56 sts)
Rnd 52: k
Rnd 53: [k9, k2tog] around (49 sts)
Rnd 54: k
Rnd 55: [k9, k2tog] around (42 sts)
Rnd 56: [k9, k2tog] around (35 sts)
Rnd 57: [k9, k2tog] around (28 sts)
Rnd 58: [k9, k2tog] around (21 sts)
Rnd 59: [k9, k2tog] around (14 sts)
Rnd 60: k2tog around (7 sts)

Cut yarn, leaving long tail, and thread through needle.
Slip needle through remaining stitches and pull tight to close.

The design knitting may sound complicated, but once you get going you’ll see the pattern coming through in your work and it’ll be simpler. It may help to color in a chart, too.
Good luck, and be sure to post pictures!