How do I learn web development while having a project in mind?

I only know python. A bit about HTML. No CSS, js knowledge. I want to create a website for college just like Quora where people have their accounts, followers, write posts and can upvote them. What exact steps should I follow in 1 month time?
Should I learn backend first like flask-python or the frontend first?
If I want to use bootstrap framework in the frontend, do I need to know css and js too?
In a nutshell, what exact steps should I follow to build the website and learn as I go?