Preparing a file at the right size for a wrapped canvas

[Jenn Ream]

I'm working is CS6 and I've followed the instructions detailed in this article: http://www.damiensymonds.net/tut_canvas.html
I'm getting hung up on this step at the very end:

"Make sure you’ve got the topmost layer selected, then press Ctrl Alt Shift E to make a new combined layer above them all."

I'm on a Mac and it doesn't appear that those shortcut keys are making a new combined layer at all, but doing something else altogether.
Could the shortcut commands be different on a Mac or is there another (more manual) way to accomplish this?

Would it be okay to merge the layers or flatten the layers and then move onto the sharpening step?

Thanks for any help or advice! 

[Damien Symonds]

Sorry, yes, it's Cmd Opt Shift E.

[Damien Symonds]

I've just updated the article with that.  Thank you.

 

[Jenn Ream]

Thank you!