FWA 510 5G - Setting up network share doesn't work

Good evening

I have a FWA 510 5G router. Works perfectly except network share.

Today I connected a new 2TB SSD externally to the USB port. Formatted with FAT32.

As can be seen in the picture, the SSD is recognized by the router.
But I can't create shares, only new users.

The Create Share function is not there.

What am I doing wrong?

Thank you very much for your help.