When you create a new test, you might want to clone an old test or copy few questions from it. Here is how to do that.
Create a new test as usual.
Head over to Questions section from sidebar.
Once there, click New Question dropdown and select Add From Library.
Expand Recent Questions option from the side.
Here you will see all your previous tests, select the one you want to clone.
For each task, click Pick Task to add it to current test.
Close the library after you have added all the questions you need.
Note: You might want to change the Time Limit of the test as you see fit after this.