How can I program an exam on Moodle so that I do not have to make it manually visible when time comes?
I would also like to include a PDF file in the exam, but I only want it visible at the opening time
Answer
If you plan on using the Assignment type of activity, you can upload the PDF as an additional file in the Settings menu of the Assignment itself. You can then flag the Only show files at submission option, which will make it available only at the opening time of the submission.
In order to further limit the access (to avoid students seeing the PDF beforehand), in the very same menu you must add a date-based restriction - from the Restrict access section of the Settings - selecting the beginning time and date of the midterm as a condition. This way, you can keep the activity visible, as it would not be accessible until the set moment.