• inside file lessons.constants.js we have LESSONS, it's object from which we should build sidebar(lessons tree)

• according to content lessons tree should be multilevel

• each tree element should be clickable: -- when you clicking on category(isCategory=true) - category should show childrens -- when click on lesson(isCategory=false) - we should display name and content of lesson on page(under content you should multiply name 1000 times to keep page NOT empty)

• sidebar and content should have 2 independent scrolls, when content huge and you scrolling it - sidebar should stay visible, when sidebar huge and you scrolling it - content should stay visible

• inside file lessons.utils.js we have function checkIfPrevQuizzesEnabled, which detecting if ANY prev lesson have enabled quiz(quiz_enabled=true), if YES - we should mark menu item as locked

You can use any modules, frameworks, instruments which you likes, you can use React/Redux/Mobx/SCSS... or just plain JavaScript/CSS.

As a result we should have page similar to this: