* Google "[console] roms archive.org" (for example "SNES roms archive.org")

* go to one of the archive.org pages that comes up.

* On the left look for "Download Options". Find the "ZIP" that shows a large number of files. Click on the word "ZIP".

* A list of rooms will show up.. download the ones you want.
(HINT: DO NOT DOWNLOAD THE FULL ZIP unless you want hundreds of games y ou'll never play)

* Move them into your iCloud or other 'cloud' storage.

* in the Delta App click the + icon (top right corner). Browse to your cloud drive, select the rooms, click 'open'.

done!