Unfortunately endnotes don't translate over right now upon import, but footnotes will be automatically detected and uploaded.
Fortunately if you're using endnotes in Word, it's super easy to convert them over to Footnotes.
Make a copy of your Word document (if you don't want to alter the original).
Open this file in Word and click the References Tab. Click the expand menu icon in the Footnote/Endnote Section.
Click Convert, then select 'Convert all endnotes to footnotes' and click OK.
When you upload this version to Atticus, all notes will be recognized and added to the text, you can then select their location on the Formatting Tab.