There are two ways of doing this (I've never done it myself, I'm reading from the manual and my own knowledge).
1: You can create different walking views with the same graphics, just different sounds for the footsteps.
2: You can manually change them depending on what region they're on by using ViewFrame.LinkedAudio.
The easier approach is to use number 1, if you're not that keen on scripting anything.
As for checking and changing the walking view or changing the ViewFrame.LinkedAudo, it should be done in Repeatedly Execute Always where it'll still change during blocking moments. Look up repeatedly_execute_always in the manual.
1: You can create different walking views with the same graphics, just different sounds for the footsteps.
2: You can manually change them depending on what region they're on by using ViewFrame.LinkedAudio.
The easier approach is to use number 1, if you're not that keen on scripting anything.
As for checking and changing the walking view or changing the ViewFrame.LinkedAudo, it should be done in Repeatedly Execute Always where it'll still change during blocking moments. Look up repeatedly_execute_always in the manual.