I have noticed that, in terms of rating, the country with the highest average on Codeforces is China. However, when I check their profiles, I often find that most of them, from CM to LGM, participate almost exclusively in contests on Codeforces.

Of course, success doesn't come overnight, but I want to know—what was your playground when you just started?

Or which platform did you find most educational for learning competitive programming effectively ?

Any resourse that will help ?