The following example is showing importing a list of SSN matches
For other identity types you would follow the same process but with another identity type in your list you export so you can determine the other identity type's ID number.
The Import from CSV functionality is designed to work with a file that was exported from the console and not from a list of manually created file hashes or ascii matches.
To import a Global Ignore List of Matches:
Have a Global Ignore Match List that has SSN in it.
Save that exported list by selecting the list and selecting to Export it at the top of the screen.
In the exported csv you will see that the SSN is a type 1001
You would then edit your exported csv file to add other SSNs
Save the file
Import the list
You can see that it then will import the list and create the newly named list with your entries