You first need to create an account at a licensed online casino. Then, deposit funds to your account through an accepted payment method. Choose the slots game you want to play, start it up, and set the size of the bet. Now, you just have to press the spin button to play one round.
Yes, online slots have created quite a few millionaires over the years. Some games can have progressive jackpots worth millions of dollars and it only takes one lucky spin to win the entire amount.