Custom values are values that should be modifiable by gameplay effects but are not integrated by the system at default. An example is MaxWalkSpeed, this variable is in the movement component from Epic games. To make it dynamically modifiable, it must be integrated into the system.
Requirements: your value must have a base value that represent the value without modifiers.
Create a new entry in E_ModifiableValues that describes your value.
if the value is in a component or similar, the dispatcher must be bind manually.
Bind the dispatcher manually, you will need a reference to a gameplay effect component.
In most cases (in the main components) I use the get owner -> get component by class function (see attatched image). This only works if the owner has a gameplay effect component.