using Mainstage for playing backing vocals live

hiya

i'm trying to figure out the best live set up my music so bought Main Stage 2 as it was cheap and seems simple to use.

however i'm not sure where to start!

my music is quite simple and minimal, but has a lot of backing vocal harmonies running alongside the lead vocal, so this is what main thing i wanted to use Main Stage for.

I'm looking into buying a USB audio interface and also have a midi keyboard, so wondered if anyone has any experience or knowledge of this kind

of set up and where to begin!

thanks in advance for your help!

ellen