Here are the steps to translate .csv files.
1. Create a translation project
Login to your POEditor account, create a new translation project and add a language.
2. Import .csv file
Use the Import functionality the project page to import your .csv file, with translations in the language you created.
If you .csv file contains string IDs, the translations you import will be automatically suggested as Default Reference Language. You can change the DRL in Project Settings.
3. Add contributors to translate the .csv file
Add the desired languages for translation, invite your contributors to join and start localizing your .csv files.
Whenever you like, you can export each language using the the Export function in the translation page.