I have been hoarding a cork board I saved from the trash.
I just used my heavy duty staple gun and stapled the burlap to the back of the cork board. I did the sides first, making sure I left some room around the corners. The cork board had great round corners, I wanted to make sure it stayed that way. So this is how I navigated the corners:
3: Then I folded the two sides, stapled...
4: and you still have those nice round corners.
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