It is widely described on the Internet. Try searching for "Virtual Box share files", i.e.:
https://www.howtogeek.com/189974/how-to-share-your-computers-files-with-a-virtual-machine/

2017-09-08 18:07 GMT+02:00 Fereshte <fereshte.ramezani@gmail.com>:
Dear FreeSurfer experts
I've tried using FreeSurfer on windows with VirtualBox. I need to transfer some files on my windows to use in FreeSurfer. I've seen the same question in the frum but not appropriate answer and i couldn't find any helpful instructions on net either. 
I'd appreciate your help with it.
Regards

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