I think this website can help you : Crown of O's (series) | Roblox Wiki | Fandom
For get a crown you must have an average number of players indicated on the site over a period of one month. If a game has just been created and already has many players, you need to wait a month to find out the average number of active players for that month.
It’s uncertain when they actually give you the crown. I got a game that has had 30k+ monthly active users (MAU) for the past few months yet I still haven’t gotten the crown for 10k MAU (the adurite crown)
Crowns are based on monthly active users not on the current people in the game
For example if your game reached 100 unique visits (100 different people joined) then you would be eligible for the first crown
Roblox takes some years for you to receive the crown which is just too long
Roblox support also tells you to contact devawards@roblox.com however i emailed this email before and got no response a year ago but they are still giving them out appearantly