Calibre librairy sync

Hello dear booxers,

I try to sync my calibre library with my Note air 2 AND keeping the structure of my library (my collections).

When I just transfer an ebook directly to "send to device", it does copy the ebook to the boox but the structure of the collection is not respected. Actually there are non...

So if I synchronize 30 ebooks they will be all in the same folder/collection on the boox and not sorted by collection.

Do you have any idea ?