At first you will have a balance of 0 Bitcoins. Each hour you can hit the ROLL! button and you will get a small amount. Well, this small amount can be increased so that it is higher and higher. This is mostly done using the MULTIPLY BTC. The higher the bet you make, the higher the percentage increase required to raise the minimum amount on the ROLL. During the first few times, you can bet everything on MULTIPLY BTC since you can double the amounts and if you lose it will not be a very big loss. Once you get at least 800 or 1000 satoshis, you can start doing the trick. Remember to refresh the page every 5 or 10 minutes, and keep in mind that it is not a 100% reliable trick, so I recommend you have many satoshis before using it. In MULTIPLY BTC, click AUTO BET, and set the settings as in this image:
 

With this you will double the amount bet each time you win, and if you lose, your bet is multiplied by 2 until you win. As your number of satoshis increases, you can place bigger bets, but I recommend starting like this. This will increase the profit on every ROLL you make. For example, I have managed to increase it a lot, and at least I am winning 90 satoshis with each roll:
 

2. Exchange REWARDS

With each spin you make at FREE BTC you will earn points that you can redeem in the REWARDS section. My recommendation is to use the FREE BTC BONUS, when you have at least 320 points, since it increases the amounts of the FREE BTC ROLL for 24 hours, and if we add that to that the amount will already be increased by the percentage that we have raised in the MULTIPLY BTC, the gains can be big.