The embed code does work! The screenshot of the embed on my test site is below
If the image is not visible check this http://i.imgur.com/8Lm0048.png
How to go about it (it is long therefore brace up! :-) )
On the page where you want to embed the code.
Click on an Insert Point to add the Code Block.
In the pop-up titled "EDIT EMBDED", hover the mouse at the right end of the text box and you should see "</>". Click on it.
This would open another pop-up titled "EDIT EMBED DATA".
In the multi-line text box paste the Society6 code
In the "EDIT EMBED" pop-up click the save button.
Click the save button to save the changes made to the page.
Since a script has been embedded log out of the squarespace admin and visit the page you embedded code in.
"tadaah" the code should work.
If for some reason the steps do not work let me know and I will try and walk you through the process.
Cheers, Pali Madra