having working external hard disk which is accesble in macOS and windows ( might be NTFS but not sure ) and used to be mounted in windows and mac but when tried in ubuntu ; it gives error
lsblk
show /sda/sda1 is the address ; here is part of output

created a directory ~/external we when write
> sudo mount /dev/sda/sda1 ~/external/
mount: /home/user/external: special device /dev/sda/sda1 does not exist (a path prefix is not a directory). dmesg(1) may have more information after failed mount system call
