When creating a new test you can either allow us to automatically pick questions for you or you can create an empty test and choose the questions yourself.
After you have created a test, open the test and head over to Questions section from the sidebar.
Once there, click New Question dropdown and select Add From Library.
Picking a Question
You can either pick a question from our list of questions or you can pick from your previous tests if you are trying to make a similar new test.
Our questions are categorized according to their difficulty. Here we are viewing the Easy ones. You can click a task to read it in detail or click Pick Task to add it to your 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.