You can't find directions because it's patented.

Go to a crochet forum and ask. I have seen them made with bear can pieces, but not with the cardboard case.
Google crocheted hats.

I looked at the beer hats site and think you can figure it out if you really want one. They showed the inside of the hat. Since you're making it for yourself and not selling, I don't think there is any copyrite infrigement. They how the bottom side of the hat if you look at sizing. They mention staples. I would also use clear packing tape.

Here is a link that might be useful: Beer Hats site.

I bought one for my son...and I have to tell you... I would have paid double... it is so very well made and the sealer they used is like a hard plastic.... he recently moved to Calgary from Nova Scotia.... where better to wear it...lol
He was enthralled by how tastfully it was made
Not what you asked...but ifelt I should make mention of it

hi
thanks I missed this before boy o boy back in the day I would have distributed these how cool is that sobriety has me leaning towards the "root" beer version but still a looks like a sturdy hat thanks .Rick

I picked one up for 30 at a BQ Festival in Owensboro. I would of paid even more the quality was amazing. Leather trim also! They have a web site www.bestbeerhats.com they are awesome!!