the only fault I find with these instructions is that you're told its OK to do it while holding the item in your hand, in your lap.
For the sharpening-challenged, this is probably not a good thing.
My point is simple- it's very difficult to avoid 'moving' the piece you're sharpening while running the file across the edge- if you do that, you have a tendency to round the edge, rather than sharpen, and to sharpen unevenly.
It's a much better idea to place the head against something like the end of a stair railing, or a bench, or whatever you have handy that will not move when you file against the head, and in that way you can get even pressure while filing the blade from end to end.
Also, if you do it outside, it's a lot easier to see the burr - it should look like aluminum foil on the edge of your blade. If you raise it up, and get it moving side to side with your strop material- cardboard, smooth leather etc- you can then see the foil edge as it peels off.
Once it does, STOP.
Also, if you are doing single bevels- ALWAYS BEGIN BY FLATTENING THE 'FLAT' SIDE OF THE HEAD BY MOVING IT FLAT ON YOUR FILE- WHICH YOU LAY ON A TABLE EDGE. THE FLAT SIDE OF YOUR HEAD IS NOT FLAT UNTIL YOU FILE IT THAT WAY- PAINT, UNEVEN CUTTING OR FORGING- WHATEVER CAUSES IT- YOU CANNOT HOPE TO HAVE A SHARP HEAD UNTIL THE FLAT SIDE IS FLAT- FOR CERTAIN.