Basic help, select folders instead of separate files/docs

I just have installed OwnCloud (QNAP).
I want to upload files form my laptop tot my NAS.
I select "documents" and then I can select files form my laptop.
I can easily go through al my maps, but I only can select separate files instead of folders.
I have at least a hundred folders with 1 tot 10 documents in each folder.
How can I manage to select folders a once?

Greetings Paul from the Netherlands
Sorry for my bad English

I think to be able to upload complete folders you would need to use one of the ownCloud sync clients.