All you have to do is
The code you have is for changing all materials of all static mesh components. But you only have one.
I want to change the static meshes of an object other than just changing the object’s materials. But I don’t have ideas where to start 
Should I create a new blueprint or edit the blueprints for changing object’s materials, as shown in the picture below?
So, I just have to add one set static mesh into it for changing the static mesh?