Hello, I haven't knitted in a long time so this will be my first project coming back. I have super bulky yarn and am trying to knit a beanie using the 2x2 rib knit stitch with flat needles. I found some patterns that include some elements but haven't been able to find something specific to what I'm trying to do.

I like this video tutorial but the weight is medium. I didn't realize how complicated it is to convert yarn weight. I think the cast on is 40 stitches for the width.

https://youtu.be/SSNp0nnWBFE

I found this pattern that includes the weight I'm using but they're using circular needles. Conversion also seems complicated. https://sheepandstitch.com/pattern/how-to-knit-a-chunky-hat-for-beginners/

I'm hoping this pattern will be simple enough that someone might have experience to let me know how many stitches I should cast on for a super bulky beanie using straight needles? I think I'll just knit a square and then tie it up at the top, like I've seen in other videos, so I won't have to deal with the reducing stitches at the top.