This depends entirely on you.
The core Study Program takes about 3 months if you do about an hour each day (there are options to do more if you have more time).
There are 10 main courses, and each course has 28 lessons, so technically it will take about 280 hours to complete all of the lessons.
I add new materials to the Academy every week and I also add ‘Quick Win’ videos in response to special requests from Academy Members.
Just do one thing a day. This will be enough practice to prepare you for the exam.
You can watch the videos as many times as you like, and do the exercises/worksheets over and over again until you feel confident that you’re getting the language, grammar and vocabulary right.