Need to sharpen my Craftsman 18" 40cc chainsaw and I've never done it
before.

The manual says to use a 4mm (5/32") round file at 25 degrees but it also
shows a guide.

Googling, I see utube videos, some of which use the guide and others can't
stand 'em; while all seem to use a different guide with a flat file to even
out the depth gauges.

Where do YOU guys get your chainsaw sharpening kits and which ones do you
prefer?