ALSV4_CPP Footstep sounds - TwitchBlade/ALS-Wiki GitHub Wiki
Footsteps are associated to each animation with an animation Notify, but in ALS there is a specialization of the notify, which is custom, and shows how you can have custom effects associated to an animation.
This is visible in : AnimSequence'/ALSV4_CPP/AdvancedLocomotionV4/CharacterAssets/MannequinSkeleton/AnimationExamples/Base/Locomotion/ALS_N_Walk_F.ALS_N_Walk_F'
As you can see in the picture there is a special Footstep , you can add one just by right-clicking on Notifies lines and then select "Add Notify..."->"Als Anim Notify Footstep".
If you select it, you see on the right the properties including some custom attributes which can be used to configure the sound.
The custom Anim Notify is in C++, and derived from UAnimNotify base UE class.
plugins\ALSV4_CPP\Source\ALSV4_CPP\Private\Character\Animation\Notify\ALSAnimNotifyFootstep.cpp