Hot to compete challenge win contests with different characters?

So on Squid Games Unleashed under the challenges there is one that says win contests with different characters. I've completed that once and then I play a different character and I play games and even have been the last one standing and it still won't complete. What does it mean by "Win Contests" then? Are they talking about if they have a certain promotional. Where they're doing an event or something? Because I've tried two different characters and have played games and have been the last one standing with both characters and it still won't complete and I have that one as my last one to complete everything up to week 3 until we get to week 4.