Underbody shield replacement

welcome!
those don't help at all. i would look up an exploded parts digram on line, and try to figure from there which pieces you need.

 

It's hard to tell which part of the engine splash guard you need from the photo you provide.
You need one of the parts listed here: https://parts.olathetoyota.com/v-2017-toyota-prius-prime--plus--1-8l-l4-electric-gas/body--splash-shields
and this https://parts.olathetoyota.com/oem-parts/toyota-fender-liner-5387647140

You will also need fasteners. But the easiest way to identify the exact parts you need to replace would be to ask the dealer for an itemized parts list and quote.