The GamerCoin (GHX) bonus lasts for a whole month, it is activated every day at random and lasts until the daily bonus pool is exhausted.
The bonus is 20% of the income from mining and it is calculated only from the funds mined during the time the bonus is active. The maximum bonus that a user can receive is the equivalent of $30 in GHX per day.
Here is an example - if you mine $1 during the bonus period, you will receive $0.2 more in GHX! That's a total of 40 GHX!
If you want to withdraw your money to Metamask wallet check how to do it.