To import your past survey responses from Delighted into Retently, start by exporting a CSV file with those responses from Delighted. You can follow their official tutorial on exporting survey data: https://delighted-help-160b834b9adfde78ebef1528.helpscoutdocs.com/article/544-exporting-data#how.
When exporting the survey data from Delighted, choose the "Survey responses" option, as Retently doesn't support the "Sent/Scheduled surveys" option.
Once you've exported the CSV file from Delighted, the next step is to upload it into Retently. Please watch the screencast below and feel free to follow the steps show in the video to ensure that everything goes as expected.