The input routing has to match the inputs on the hardware.
E.g. choose input “1” when you plan to make a vocal recording, and choose “2” for the guitar.
Since the iTrack seems to support stereo output only, leave the output setting untouched.
You have to create one Audiotrack, tab Mono Input (1) for Input 1 ( Guitar input Focusrite )
then you have to create a second Audiotrack, tab Mono Input (2) for Input 2 ( Vocals Input Focusrite )