It allows you to choose whether to trade in your actual brokerage accounts or using a trading simulator. The Live Trading button will log you in to your real funded brokerage accounts; trades will be real and profit and losses will affect your funds. To practice trading with simulated accounts, click on the Simulated Trading button; any orders placed will not be real, nor will any profits or losses be real.

Keep in mind that pressing the Enter key on the keyboard after entering the password will default to Live Trading.