Post-Submit HTML

I am tweaking a shift-trade form for our fire/rescue department and need an email to go to the person submitting the shift-trade, person they are trading with, and the admin captain. I would like the emails to be sent once the submit button is clicked and not take them to an email app. I would also like the emails they get to be able to reply all including the emails of the two parties trading and the admin captain. The two doing the shift trade email addresses are in the form and the admin captain's email is where the form goes when they hit submit. Clear as mud?

Does this code to make this happen go under Advanced, Post-Submit HTML? If so, what does this code look like?