Not sure if there are any tutorials for how to do it on the web.
The trick is to drop from ledge and imidiatly double jump and hold in towards the stage.
The double jump has to be the regular version. Not the backwards double jump.
If you don't input the airdodge, Ganon will NIL (No Impact Land). It is around the timing he will land you want to input the airdodge.
Since Ganon's ECB (Environment Collision Box) is so busted you can input the airdodge while holding a full horizontal direction for max distance on your ledgedashes.
Abusing this you can also do safe RLD (Reverse Ledgedash AKA. Hax Dash) by holding diagonaly up when airdodge so if you miss the timing you will regrab ledge instead of dying.
Hope this helps