As much time as you want. The more time you out in then the better, but the more likely younare to get bored and give up. Its a fine line between enjoyment and boredom when you put a lot of hours in.
It also depends on your natural ability at understanding coding concepts. If you can understand and apply them easily then you won’t need to spend as much time every day.
Just find a happy medium and do what you feel comfortable with.
Depends on when you want to be a pro. If you want soon, 30 to 50 hours a week is needed. If you don't care, 8 will get you there. The less you do in a day or month the more time it costs you to get back up to speed prior to learning. Pro might take some people 100 hours while others might need 1000. Can't predict what you might need.