The following steps will help you import your notes from Simplenote easily.
Open Simplenote app on Desktop or Login to https://app.simplenote.com.
Go to sidebar and click on Settings.
Tools tab in Settings
Export notes to download your notes as a .zip file.
Go to Notesnook Importer and select
Simplenote from list of apps.
Drop the .zip backup file you exported earlier from Simplenote in the box or click anywhere to open system file picker to select the backup and click “Start processing”.
Once importer completes processing, download the .zip file.
After you have downloaded the
.zip file, go to Notesnook app > Settings > Notesnook Importer and click on “Import from ZIP file” & select the .zip you downloaded earlier.
Once importing completes you should see all your notes in Notesnook. If you face any issues during importing, report it on github.