Select the rectangle.
Right Click
Select Web Properties
Select Placeholder tab
Select Replace with HTML Code
BODY button
Paste in:
<iframe src="https://docs.google.com/spreadsheets/d/1mvfL3m72wQmTj5xaTBGsnsLMhGi-0o0rLPlSBRV6xq0/pubhtml" height=920 width=860 scrolling=0>
<p>Your browser does not support iframes.</p>
</iframe>


EDIT: If you can't see "web properties" in Photo Designer 10, with the rectangle selected , go to Web Properties under the Utilities menu and continue as above.