You seem to have asked several questions.
1) Yes, quizzes can be timed. See https://docs.moodle.org/39/en/Quiz_settings#Timing.
1) Yes, quizzes can be timed. See https://docs.moodle.org/39/en/Quiz_settings#Timing.
2) Yes, you can provide detailed instructions by using a "Description" question type as your first question.
3a) Yes, students can upload a file into a quiz question. But you need to use a question type that supports an upload. The essay question type supports file uploads.
3b) Alternatively (to #3a), you can create an "Assignment" and have students upload their Excel files. Using #3a or #3b will depend upon your situation, and how you prefer to grade. The advantage of using the "Assignment" is that you can "bulk download" the files and grade "off-line."
