Hello -- I cant help with you MAC Question but for importing -- its pretty easy -- I too an fairly new here and just getting going. The First thing to do is Click on the Help Link -- then on the selling link on the left hand side . In the Video section there is a video titled "How to import auctions into Ninja Lister". It makes it pretty clear. There are many other videos there that will help with everything from Importing to setting up a store -- editing etc.
Good Luck