Changing the attachment clothes for a character

I need some orientation. i need to have a character, with two basic skins, male and female. Then I need to add clothes which can be customizables, the clothes will be the same images for both skins. The skins only are the naked body.

Which is the best way to do it?
Do I create two skins for the naked body? And then how I attach the clothes. Do I need images into slots for the clothes or skin placeholders into slots?

Also how i change the attachment in one slot? I am trying skeleton.setAttachment(“eyes” , “eyes closed”);

with goblins sample but give me errors. what does “Eyes closed” need to be? An image into a slot, the filename of the image?

It is confusing and spine has no examples how to do this, the sxamples only shows the character animations.

Anyone has basic code which shows how to do this basic things?