I don't have a tutorial for the MWK (Matthew Walker Knot).
Here is how to tie the over two crown-diamond knot
Over 2 TutorialTo tie the over two crown knot (middle section of the fob)see steps 7-12.
This knot is very secure as it is.
If you want to make it even more secure make the wall knot in the crown and wall a under two variety.
Under 2 Tutorial