These are a very easy way to upgrade Puppy for those on dialup or other slow or bandwidth-limited Internet connection.
The "catch 22" situation is that you first need to have a running
Puppy, so the first time does require that you download a complete
Puppy live-CD .iso file.
Once you have a running Puppy, look in the 'Utilities' menu, you will
see an entry 'Xdelta file difference manager' -- run that, and you
should be able to see what to do next.
The Xdelta GUI window is simple "drag and drop". For example, say that
you had previously downloaded 'wary-5.1.3.iso' -- find that in the
ROX-Filer file manager, then just drag it to the top box.
You need to download the delta file, 'wary-5.1.3.iso___wary-5.1.4.iso.delta', then same thing, drag it to the bottom box.
Then click the 'GENERATE' button, and after a short time there will be
completion message, then you will have file 'wary-5.1.4.iso'
The beauty of this is that 'wary-5.1.3.iso___wary-5.1.4.iso.delta' is
fairly small (in this particular example it is 22MB, but in many cases
it is much smaller), whereas the full 'wary-5.1.4.iso' file is 120MB.