Just open the web browser and read available documentation (points 1, 2 and 3 are covered):
The biggest difference between Tradestation and us is that Tradestation does not allow you to use their software independently. You must trade with them. All their functionality is forcing you to trade with them only as they make money on commissions and all they care is to get more commissions from you.
AmiBroker is independent software, we don't charge commissions from your trading, so AmiBroker functionality allows you to develop system that are broker-agnostic. You can create system that uses certain level of abstraction and is not tied to particular broker. That's why automated-trading interface in AmiBroker is separate from the main program. With AB you don't need a broker account to backtest your strategies. The idea is that AmiBroker is focused on system research, backtesting, optimization and validation that is broker-independent.
As for auto-optimization (re-optimizing as you go) it is of course possible with AmiBroker, but that is unrelated subject to auto-trading as these two things are fully independent. Consult manual for info on optimization.
Also these kind of "generic" questions should be sent by email to support address.
If you sent your query to support you would get that from our AI.
To automate order execution in AmiBroker, you would need to use an automated trading interface add-on. You can find instructions on how to configure AmiBroker to work with Interactive Brokers TWS in the AmiBroker manual, which can be found on our website.
As for reliable brokers that work with AmiBroker, we officially support auto-trading with Interactive Brokers.
Regarding the execution of orders, by default, orders would be placed at the time that you specified by you. There are special order types that you can use to trade on close. And you can place them say 5 minutes before if you wish.
If you're looking for code examples, you can find them in the AmiBroker User's Guide and on our website.
I hope this helps! Let me know if you have any other questions.