Self Explanatory but thought I'd add an overview.
One of the easiest achievements but will take a bit of time. I got this about half way through progression level 8.
Enter any slot machine and hold SPIN! button for a couple of seconds, a drop down menu will appear. You can now select the amount of auto-spins you want the game to do, I generally selected 100 not 500.
This achievement will require you to pay some attention to your phone as every time you win a chance at the "Bonus Game" or some "Free Spins", the auto spins will stop. Once you have completed the Bonus game or the free spins slot, you have to repeat the set up process as the spins would have stopped.