To create a copy of an existing test plan,
1) Click on "Your Plans."
2) Search for the plan you want to create a copy of.
3) Hover to the right of that plan name to pull up the 3 purple tool tips.
4) Click on the "copy" icon as shown below to create a copy of the plan.
Select Plan Name and Project
Input the name for the new test plan and select the project to put the copied plan into. You can create a new project by selecting "Create a new project...," and typing the name on the popup screen.