how do I trade e-mini?

E-mini's are just smaller versions of the full size contract. You buy/sell them just like you would the full size contract, but because they're "mini" the profit/losses are less as are the margin requirements.For example, the S&P 500 is 500 times the contract. So, if you have a 30 point move in the full contract, you'd have a $15,000 profit or loss (depending if the 30 points moved in or counter to your position). That's 500 x 30 points = $15,000/contract. The margin on the S&P 500 would be about $25,000 depending on volatility. On the Emini S&P 500, it's 100 times the contract. So a 30 point move would be $3000 profit or loss and the margin would be about 1/5 the value of the full contract.You trade them just like the full sized contracts, they just offer greater affordability to the individual investor.