You determine your own convenient time. It could be 15 minutes a day. It all depends on you, your goals and your ability to learn.
All lessons are recorded so that you can build your own schedule and watch the lessons whenever you want. You watch the lessons from your phone, tablet, or computer.
Yes, you will be able to ask questions in the lessons - and the teacher or site supervisor will answer you.
Yes, that's fine. The only thing you need is a desire to learn. Lessons in modules (categories) can be ordered by complexity. The first will be the basic lessons.