First, you need to correctly place all the files from the archive to ComfyUI_Prompt_Gallery custom node data folder.

Put "sluttyout3.yml" in "promptImages" folder and images from thumbnails folder put into "promptImages/thumbnails/ponyxl/sluttyout3"

Then you need to add some lines to the ComfyUI_Prompt_Gallery plugin scripts. In the custom node folder, go to the "web" folder and open the "prompt_gallery.js" file. Around line 22, you'll see an array of yaml files, yamlFiles . You need to add a new element to it.

{ name: "sluttyout3.yml", type: "SluttyOut", skipLevels: 0, section: null, order: 11 }

Then restart ComfyUI

Open custom node browser and you will see new section

It's a bit complicated)