This tool is used to create a config for BPLoader, which is used to load the blueprints from different mods while keeping compatibility with each other.
To create a config you need to add your files. To do so, either click select files, or drag and drop the mods' .pak files onto the page. When a mod that uses BPLoader gets added a path will appear for that mod's blueprint. Finally click generate config to generate and download the config file which should be placed in your ~mods folder.