I think there's been a breakdown in communication here. Maybe several.
Stu's recipe appears to be a Mexi Hamburger Helper style of thing. I'd
add a can of corn and a can of red beans, myself. I'm also not a fan of
"one pan" pasta dishes, so I would precook the shells before adding
them. I'd turn the whole thing out into a casserole dish, slap some
grated cheese on top and heat it in the oven. I'd probably use medium
or small shells.