Tutorial For Editing Quests ?

[nouser]

I know its possible to edit quests. but i did not undestand the instructions. can someone provide a tutorial ? Its something which would be very useful  for all players who want to change quest decisions.  In my case i want to change hiravias disposition from galawain to wael. How do i do that?  My last save is in burial island right before the battle with Cathden at the grotto of echoes. So how do i edit the game ?

Edited October 24, 2018 by nouser