Beginner

• Read a wikipedia article for selected topic
• Read associate wikipedia article if you want to deep dive
• Read interview questions (someone made one big list for you on GitHub)
• Explore cheatsheet

Intermediate

• Read 3 blog posts on selected topic from Dev.to / Medium
• Watch 1 playlist (complete the playlist, please) on YouTube
• Take a paid course from Udemy or any other source if possible (or download the popular one free from torrent / freecoursesite)

Advance

• Learn the standard
• Write a blog on dev.to / personal website (or any other platform)
• Make a video and publish it to YouTube