Copying another user's set
To make an editable copy of someone else's set, or another version of your own set, use the Copy tool.
Copy the Set
To make a copy of another user's set, go to the set page and click on "Copy" in the Tools section.
If you are making a copy of your own set, this option will be under "More."
You can then edit your copy of the set, or just click "Done" to save the set as is.
The new set will show your username next to the title, but you can always see where is was copied from by clicking into the Info tab.