a little update - found on the russian forum.
In order to transfer files between your computer and the device via bluetooth, just do as follows:
1) first of all, make sure your computer recognises the device (go in configuration\connectivity\bluetooth access and select visible, tehn follow the instructions on your computer)
2) to send a file from the device to the computer: go into the library, select the file you want to send, give a long press, and when the little menu appears select file\send to: at this point the device will list the devices available for connection, you select your laptop, and the transfer is done.
3) to send a file from your computer to the device, simply select the file(s) you want to send, right click (if using windows - I do not know about other operating systems), then select "send\bluetooth" from the context menu: a window will pop up asking you to select the bluetooth device you want to send the file to (mind you, this one does not always work).