How do আপনি give your club a background color?

I'm not sure if you're asking about individual profiles অথবা clubs. If it's profiles then the other answer is correct. আপনি need 50 স্বর্ণ to set a basic colour background, and 500 স্বর্ণ to set an image as a background.

সংগঠন can't have backgrounds until they have over 5000 members. Then you'd need to make a মতামত and have all the members vote for their preferred background. আপনি can't simply set your own choice, even if you're the one who initially made the club.

Should be this here.