Trouble Adding Persistence

Hello everyone,

I've recently installed Kali Linux 2022.4 on a 64GB USB drive. I'm able to live boot into it and use it without issue. However, I'd like to add persistence in order to save my files and configurations between uses. I'm able to follow the instructions listed at https://www.kali.org/docs/usb/usb-persistence/ up until the end of Step 4.) when told to "create the configuration file to enable persistence" by inputting the following command:

kali@kali:~$ echo "/ union" | sudo tee /mnt/my_usb/persistence.conf

This line returns: File or directory does not exist / union

I'm quite new to using Linux, so I'm at a loss here. Can anyone provide any guidance or insight on how I can correct this to enable persistence?

Did you boot the USB with the persistence option in Grub?
If you didn't, then it didn't mount the 'Union' at boot time for it to be later written too!