How to put a character creator in game

As stated how would you implement say a Black Desert Online character creator. Ive been looking and im either looking in the wrong places or just blind.

You build all the various swappable parts/assets as skeletal meshes, that all map to the same skeleton.
Then you import them all into the engine.
Then you build a GUI that lets the user select between all the available choices for each body section.
If you also want sliders for shape, you build those as morph channels.
If you also want control for color, then you make tinting a part of the material for the various body parts, as a color parameter.

Alright. Seems easy to follow. Except this is my first time hearing morph channels. Would you mind explaining them?