Hi Maryanne, there should be a manual in the box, and you'll definately need it. If for some reason the manual is missing, you can download and print the manual from the Harbor Freight website. It's not an easy manual to follow, though, so read on...

Many folks at this forum (myself included) believe that it's risky to build the kit as per the manual, without any further reinforcements, if you want to avoid problems caused by wind damage. This forum has many posts with excellent tips regarding these reinforcements, and they were a life saver to me as my husband and I built our HFGH. I tried to many of these assemble tips in my blog:
Building our Harbor Freight Greenhouse

Here's a list of helpful links I've saved, posted by other folks who have assembled this greenhouse. They're all worth reading, and I'm sure you can find more, by doing a search for "HFGH 10x12".

Gardenerwantabe's thread on HFGH modifications:
A Guide to the Modifications of 10x12 HFGH
...and a link to his photos:
Gardenerwantabe's HFGH photos

Laserfan's thread, with links to his photos:
HFGH 10x12 Lessons Learned

Oraylawson's thread, with links to his photos:
10x12 HFGH

Troykd's site:
Building our Greenhouse, an Adventure in Pain

FoxesearthÂs blog:
HF Greenhouse in Progress

Joe Urda's site:
Harbor Freight Greenhouse

Web4debÂs site (astonishing what a technologically gifted person can accomplish!)
Building the Harbor Freight 10x12 Greenhouse

I hope this helps!
Sheri