Boris Its not that simple, you need to have a midi output from your device ie ipad connected to the midi input of your helicon 3, once you have this connection working then you write in to ST3 text editor the midi commands you want to operate your helicon 3 , you need to look at the helicon program change requirement for which program you want to change to at a particular time of the song you are using, and program this in to the text editor.
So once you load a particular song and hit play the midi program change command goes down the midi route to the helicon midi input, sees this command and switches to the appropriate program you have created in the tc helicon 3,
This is a basic explanation of how it works but if you need to know the exact commands you will need to read ST3 help instructions which will give you exact examles of the commands.
Cheers Damir