Changing default variables of a child actor component

Hi all. I am very new to UE4 and this is my first-time experience using it. How can I edit the default variable in a child actor component of another blueprint actor? I was told not allowed as shown in the image below. Thanks!

It used to work in the details, but as far as I know now ( and have experienced ), you have to set them in blueprint on begin play…

Alright…I’ll try to set it in the blueprint. Thanks!