importing users from a csv excel file to workgroup manager

I was able to download from my school attendance software the last and first names of all the kids in my school(1,500). I saved the file as a csv file, how do I import all the kids' names to to workgroup manager? What special characters I need to use so that the last name and first name gets imported?For record delimiter I use tab and for attribute delimiter I use comma. I see a list of the names and the option to import the field but there are over a thousand names and I tried a few but nothing got imported. Any help will be deeply appreciated.