1 Please check if you have enabled accordion in curriculum from lms->settings, and in the course you have added only the unit and the quiz but no section.
Please make sure this setting needs sections in the curriculum.
2 Disable this LMS setting Refer : http://prntscr.com/kacupv
3 You can do this by CSV import. Refer : https://wplms.io/support/knowledge-base/bulk-importexport-wplms-via-csv/