Hello cugal,
Have you found this thread? Dewey1945 has written a great blog on the construction of his Harbor Freight 6x8:
Improving your 6x8 HFGH

And here is a direct link to his blog:
Building and Improving the Harbor Freight 6x8"

I know the manuals change for all the Harbor Freight greenhouses, over time, but no matter what they seem to stay a little confusing. There are many similarities between the different sizes, but the parts numbers are different. In case it helps, though, here's a link to my 10x12 blog:
Building our 10x12 Harbor Freight Greenhouse

I hope you will post here if you need help, as folks here are pretty good about chiming in.

Thanks mudhouse for the links! Good info!

We followed mudhouse's instructions which were a tremendous help.

Thanks so much for your tutorial mudhouse!
Please do post photos of your process cugal.

I'm glad it helped, Trudy. Looks like you have a very pretty setting for your greenhouse. I hope you're enjoying it.

Thanks mudhouse!

We love the setting of where the greenhouse was placed. Fenced in veggie garden to the right side of greenhouse and shade houses full of hostas and hosta seedlings on the south side. What more could I ask for!

Forgot to mention our female black kitten always lays on her back for lots of loving when anyone is close by....she doesnt look alive here..... No Freida, I am taking pix, not loving time now!

Lovely and impressive! (Thanks for explaining the Flat Cat too.) My best cat ever was all black; give Freida a pat for me.