Open profile settings by clicking Browser Settings button on the ribbon.
Select the profile you want to configure and proper command line parameter.
For Chrome specify
How it works. When Rapise launches a test, if required browser is not opened yet Rapise uses profile settings to launch a new process with specified command line parameters .
Also a test can explicitly open a browser with specified URL. If in this case browser is not running yet then profile settings are also used to start it.