Bluetooth won’t work in RaspAnd Nougat as I’ve said before. As an alternative – at least for transferring files between a “normal” computer and your Rpi3 – you can install and use the Teamviewer app.
1. Screenshot of my computer (laptop) desktop when I’m connected to my Rpi3 through Teamviewer
2. Screenshot when the Teamviewer app is running on my Rpi3 and files are being transferred from my laptop to my Rpi3