Your Level is assigned to you as per your DreamCoins earning activity. Once you complete the DreamCoins activity for the first time, you are assigned a Level.
To maintain your Level, you need to earn certain DreamCoins within the validity of the current Level. If you don’t, you downgrade to a lower Level.
To upgrade your Level, you need to earn more DreamCoins required to reach the next Level within the validity of the current Level. The higher you upgrade, the better rewards you receive.