internal hdd mount?

hi all I’m new here and considering volumio over my kodi install,
ive installed on usb for a trial but don’t seem to be able to access my music collection that’s on the three 2tb internal hdd of my media pc, is there a size limit or am I just doing something wrong
any guidance would be gratefully appreciated?

ok done some reading I believe I need to mount my hdd any ideas as to how to do this?

Have a look here & see if you can follow the procedure.