Step 1: Go to the "Campaigns" icon in the upper left-hand corner:
Step 2: Click on the specific campaign you would like to duplicate:
Step 3: Click on "Settings" in your campaign tabs:
Step 4: Scroll down and click on the "Duplicate" button:
Step 5: Go back to the "Campaigns" tab in the upper left-hand corner:
Step 6: The duplicate of your campaign is now located under "Campaigns":
Keep in mind that you can also duplicate your templates by clicking on the templates tab and selecting the drop down menu from a template of your choice and selecting "Duplicate"