No, what I linked is not a .csv file, this is an .apkg file. That is why it can also contain audio. It might also contain a csv file or be based on the same structure but the file ending is .apkg.
But it is called “Demo” and in the original thread it is mentioned that this is a template. A complete core deck should be something like 40 mb or more if it contains all the audio files. This file is only 1 mb and contains 68 cards.
What are you even trying to do?
This for example should be a complete version of the core deck: https://community.wanikani.com/t/so-much-vocab/12050
Since you are new to Anki it will probably be easier for you to just start with a complete core deck, get familiar with it first and then adjust the template later. Or do everything at once but you will need more than that “Demo” thing.