After becoming a validator, you can increase your self-stake of RON.
Go to Validator Dashboard > My Staking > Stake more.
Enter the amount manually or choose Max to stake all available RON, and then select Stake. The estimated reward is calculated based on your estimated APR (annual percentage rate), so you can see how much RON will return from this stake.
Confirm the transaction.
After the transaction is confirmed, you can review its details on the Activities tab or check the status in Ronin Block Explorer.