You can ask your instructor any time by submitting a question through the course support forum. The course support forum is unique for each course. The link for the course support forum is present on the bottom of your course pages. Alternatively, you can also message instructors from your course pages using the message button.
Absolutely, once you are enrolled in the course, you will get immediate access to the course and start learning at any time. There is a premium content in each course including illustrations, audio, videos and text-based information.