Add Cover From TEXT file

How do I add cover art to a batch of mp3 files using the "Text file - Tag" function?

In my CSV file I have a column with a list of mp3 file names. In another column I have a list of the jpg files I want to attach. What is the correct formatting?

My CSV file also has other metadata columns such as Artist, Album, Year etc. These are working correctly. I can't figure out how to attach the specified jpg's though. Thank you.

The bad news is: you can't - directly.
BUT: you can import the cover file name into a user defined field and then use this data to get the cover with the specified name in a second run of an action of the type "Import cover from file".
In the end you may delete the user defined field.
If you put this last step and the import action for the cover into an action group, then you can do with one call.