There are 2 kind of leaderboards: the Arena, and the general leaderboard.
Every leaderboard is reset at the end of the period.
Arena
The "Arena" is a group of 15 users that you're placed into at the start of each period.
Your ranking within the Arena is based on the number of Trophies you earn throughout the period.
At the end of the period, the top 3 players in the Arena ranking win both Credits and Coins for the next period.
General Leaderboard
The general leaderboard is based on the number of Trophies you earn throughout the period, like in the Arena.
In the general leaderboard you'll find all the users who play at OmadaPrize during this period.
There is no rewards in the general leaderboard, it's just the fame.
Period
At the end of a period every leaderboard is reset.
A typical period lasts 1 week and starts on Wednesday morning, but the duration may change depending on special events or updates.