If you are on desktop:
Firstly, use the filters above the table to locate the project that you want to copy
Next, hover your cursor over that project, and click on the copy button that appears
Your project should now be duplicated.
If you are on mobile:
Firstly, use the filters above the table to locate the project that you want to copy
Click on the more options button at the end of the row. A copy button will now appear
Click on the copy button and your project should now be duplicated