Hello everybody!

I am fairly new to this, and so i don't really know what to do.
I was following the steps to install kali onto a usb drive, but when i reached the step of
dd if=kali-linux-2019.4-amd64.iso of=/dev/disk6 bs=1m

i got the response "no directory found", and then i tried a couple more times using
"cd Downloads", as the file was in my downloads and still nothing,

now, when i try to do the steps all over again, i cannot even get past diskutil,
because then i get this

Utility to manage local disks and volumes
Most commands require an administrator or root user

WARNING: Most destructive operations are not prompted

Usage: diskutil [quiet] <verb> <options>, where <verb> is as follows:

list (List the partitions of a disk)
info[rmation] (Get information on a specific disk or partition)
listFilesystems (List file systems available for formatting)
activity (Continuous log of system-wide disk arbitration)

u[n]mount (Unmount a single volume)
unmountDisk (Unmount an entire disk (all volumes))
eject (Eject a disk)
mount (Mount a single volume)
mountDisk (Mount an entire disk (all mountable volumes))

enableJournal (Enable HFS+ journaling on a mounted HFS+ volume)
disableJournal (Disable HFS+ journaling on a mounted HFS+ volume)
moveJournal (Move the HFS+ journal onto another volume)
enableOwnership (Exact on-disk User/Group IDs on a mounted volume)
disableOwnership (Ignore on-disk User/Group IDs on a mounted volume)

rename[Volume] (Rename a volume)

verifyVolume (Verify the file system data structures of a volume)
repairVolume (Repair the file system data structures of a volume)
verifyDisk (Verify the components of a partition map of a disk)
repairDisk (Repair the components of a partition map of a disk)
resetFusion (Reset the components of a machine's Fusion Drive)

eraseDisk (Erase an existing disk, removing all volumes)
eraseVolume (Erase an existing volume)
reformat (Erase an existing volume with same name and type)
eraseOptical (Erase optical media (CD/RW, DVD/RW, etc.))
zeroDisk (Erase a disk, writing zeros to the media)
randomDisk (Erase a disk, writing random data to the media)
secureErase (Securely erase a disk or freespace on a volume)

partitionDisk ((re)Partition a disk, removing all volumes)
resizeVolume (Resize a volume, increasing or decreasing its size)
splitPartition (Split an existing partition into two or more)
mergePartitions (Combine two or more existing partitions into one)

appleRAID <verb> (Perform additional verbs related to AppleRAID)
coreStorage <verb> (Perform additional verbs related to CoreStorage)
apfs <verb> (Perform additional verbs related to APFS)

diskutil <verb> with no options will provide help on that verb

Nathalies-MacBook-Pro:~ nathalieahmed$ diskutil
Disk Utility Tool
Utility to manage local disks and volumes
Most commands require an administrator or root user

WARNING: Most destructive operations are not prompted

Usage: diskutil [quiet] <verb> <options>, where <verb> is as follows:

list (List the partitions of a disk)
info[rmation] (Get information on a specific disk or partition)
listFilesystems (List file systems available for formatting)
activity (Continuous log of system-wide disk arbitration)

u[n]mount (Unmount a single volume)
unmountDisk (Unmount an entire disk (all volumes))
eject (Eject a disk)
mount (Mount a single volume)
mountDisk (Mount an entire disk (all mountable volumes))

enableJournal (Enable HFS+ journaling on a mounted HFS+ volume)
disableJournal (Disable HFS+ journaling on a mounted HFS+ volume)
moveJournal (Move the HFS+ journal onto another volume)
enableOwnership (Exact on-disk User/Group IDs on a mounted volume)
disableOwnership (Ignore on-disk User/Group IDs on a mounted volume)

rename[Volume] (Rename a volume)

verifyVolume (Verify the file system data structures of a volume)
repairVolume (Repair the file system data structures of a volume)
verifyDisk (Verify the components of a partition map of a disk)
repairDisk (Repair the components of a partition map of a disk)
resetFusion (Reset the components of a machine's Fusion Drive)

eraseDisk (Erase an existing disk, removing all volumes)
eraseVolume (Erase an existing volume)
reformat (Erase an existing volume with same name and type)
eraseOptical (Erase optical media (CD/RW, DVD/RW, etc.))
zeroDisk (Erase a disk, writing zeros to the media)
randomDisk (Erase a disk, writing random data to the media)
secureErase (Securely erase a disk or freespace on a volume)

partitionDisk ((re)Partition a disk, removing all volumes)
resizeVolume (Resize a volume, increasing or decreasing its size)
splitPartition (Split an existing partition into two or more)
mergePartitions (Combine two or more existing partitions into one)

appleRAID <verb> (Perform additional verbs related to AppleRAID)
coreStorage <verb> (Perform additional verbs related to CoreStorage)
apfs <verb> (Perform additional verbs related to APFS)

diskutil <verb> with no options will provide help on that verb

HELP! what do i do?!?!?!?