Nucleus question about copying

I’m copying the library from my Windows machine, over the network, to the 2 TB SSD in the Nucleus.
Takes forever.

The storage is on an external USB drive, which I can plug into the Nucleus, of course.
And the Nucleus can play from the USB drive.
But I don’t want an external gadget there, don’t want a mess, my old cassette deck didn’t have any external appendages.

I can’t find a way in the Nucleus to copy from an attached drive to the internal drive, other than over the network.

Am i missing anything?