PIC32MX470F512L not appearing on harmony setup?
Seems like MPLAB harmony v3 is a new beast and the PIC32MX470F512L files were only added about a month ago.


First make sure you download the latest framework when starting a new project by clicking on "Launch Framework Downloader" whilst online
Browse for a path you want the files to download to. click on Create  Folder if it says that the path is not valid.
click next until it downloads the catalog.
Select packages required
Click on Download and next only when downloaded
Make sure the Framework path is now the same path as the one you chose to download the packages in.
Click next
enter project name, the next
select your PIC.


If you are still having trouble, I'd use MPLAB Harmony v2 which you can install separately from MPLAB harmony v3 in my version of MPLAB 5.15



MPLAB Harmony v2 supports your desired PIC