Core decks vs extensive reading

I think all you have to do to start a new Anki deck that is ready for Rikaisama input is:

Start a new deck (Create Deck)

Made sure the fields are

Expression
Reading
Meaning

(You can check/change the fields by opening the deck, choosing Add (add card) and then hitting the Fields button)

You now have a Real-Time Import ready deck. I don't think it is even necessary to make a dummy card.

Actually the fields can be called anything you want them to be - you just have to change the names to be the same in Rikaisama's anki setup (last tab on Rikaisama's options), but I am just giving the simplest method.

I agree that twiddling with Anki can be very unintuitive., but this particular operation is fortunately easy.

Note that you must have this deck open when you press one of the Real Time Import buttons (R for kanji on the front T for kana while the Rikai pop-up is active). The plugin will try to import to whatever deck is open at the time, and if the fields aren't named correctly it will fail.