The recommended platform is DAS Trader Pro through Interactive Brokers (IB). I think all the educational materials here are oriented around that setup.
If you're planning to day trade though, $25K isn't enough. That's right at the PDT minimum and if you have one red day, you'll be blocked from day trading until you bring it back up. That's probably too much pressure to perform for most people getting started.
If you plan to day trade and want to do it with $25K, then consider one of the overseas brokers like CMEG. Their commissions are a little higher but once you get up to $40K or whatever you're comfortable with, you can switch over to IB. Also, I found CMEG seemed to have less capacity for shorting, filling orders, and had more slippage. Also, they charge their DAS platform fees directly from your account. I prefer to keep those separate because otherwise it feels like I'm taking more losses than I am.