To copy and paste individual questions, open your existing test/section, go to the Questions tab. Expand all of the Advanced Search Pull-downs. Under the View/Show Options find the setting to let you add a select check-box next to each question. Check that and press the Advanced Search Button to set this option. Again make sure to expand all of the Advanced Search Pull-downs. Here you can use the check boxes next to any of the questions to select. Once selected - go to the top where the Advanced Search Pull-downs - and look for the panel where you can choose what you want to do with that list of questions. You'll see a Copy button. Press it.
Then go to one of your Sections (or Tests) - go to the Questions tab - Expand any pulldowns there - you should see a Paste Button. Use that to paste the already 'copied' questions into this new New section.