macOS Creating a Folder in Terminal

Hi, i'm trying to create a hidden folder on my external hard drive for protecting some data but having trouble even getting to the drive location

so far all i got is;

~ cd volumes
and if i "ls" i can see the "Lacie Mini" external hard drive i want, but if i type

~ cd volumes Lacie Mini , its unrecognized.

Help Appreciated, Thanks.

(mkdir .PrivateFolder)

Thank You, works great!