How can I unlock
What do you mean by unlock? If you mean the courses/lessons, you have to either go through the previous lessons first, or click the button that says "Take a shortcut." They'll test you and if you pass you can "skip" lessons.
/*According to your tag and title and description → How can I unlock html code*/ HTML code is fully open source so you don't need to unlock it by any means like reverse engineering...
How can I unlock test case in learn to code ?
I found this