Problem setting up Persistence on Kali Live USB

I have just installed Kali Linux Live 2020.3 (I downloaded it last year and my internet is slow so I don't want to have to download 2020.4) onto my 16GB usb drive using Etcher, and now I want to add persistence.
I went to the official post from www.kali.org about setting it up, and when I get to the 2nd step, I copy the command and paste it into the terminal (where I do have root privileges) and then I get this:
Attachment 4476

Code:

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du: cannot access 'kali-linux-2020.3-live-amd64.iso': No such file or directory

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I then press enter not noticing this and I am met by another error code:
Attachment 4477

Code:

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Warning: You requested a partition from 0.00B to 7516MB (sectors 0..14680063).
The closest location we can manage is 512B to 32.3kB (sectors 1..63).
Is this still acceptable to you?
Yes/No?

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I don't know what the problem is, my USB drive is 16gb, 12gb more than the recommended 4gb. I have searched the web multiple times and I still can't find a solution.

I have also used

Quote:

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fdisk -l

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to check if I have enough space, and I do!
Attachment 4478


USB Drive: ADATA UV128/16GB
ISO Version: 2020.3 Live