Here is an easy way, which work on each single distribution, to copy KaOS on a stick:

1 Check the validity of your ISO: md5sum path/to/ISO
Compare the result with that one: https://kaosx.us/pages/download/

1 http://wiki.rosalab.com/en/index.php/ROSA_ImageWriter#Where_can_I_take_it.3F

2 Put the tar.xz file into your Downloads folder, extract it and click on "RosaImageWriter"

PS: If your distro open the file in a text editor, close that one, go into the Terminal and run:
/home/$USER/Downloads/RosaImageWriter/RosaImageWriter

3 Write the ISO to the stick

(ROSA Image Writer will try to unmount your stick, once finished)

4 Check the validity of your USB port and stick:

Open the stick in your file manager, in order to remount it and then run:

df (in order to see where the stick is mounted, mostly on sdb)
cmp -n stat -c '%s' path/to/ISO path/to/ISO /dev/sdX (replace the X with the mount point of the stick)

If you simply get no result, is your stick and the port valid.