We are sorry to know that you are having trouble configuring the addon. Don’t worry we will help you out to make this work. We have released an updated version for the addon. Please update to version 1.1 to fix the problems you are facing right now. If you cannot see the update notice then visit this URL http://yoursite.com/wp-admin/update-core.php?force-check=1
Moreover, are you using the standard template to import your quiz questions? The standard template is available inside the learndash-quiz-import-export/Documentation with the name Standard Template.xls, a guide is also available to create the standard template in the same folder. Try importing the standard template after the update to version 1.1. A new quiz with the same name as the file will be created when the import is complete. If you import the same file again it will override the previous import.
If you face any issue, feel free to get in touch