To connect your TradeStation account to Option Alpha, go to Settings --> Trading Accounts and select 'Authorize on TradeStation.com.'
You will be re-directed to their website to log in using your TradeStation username and password.
Once your accounts are connected you can select your TradeStation account when creating a new bot to trade live.
You can authorize one set of credentials (username/password) per broker. You can connect multiple accounts with the same username.