Photo blog with CMS and lightbox question - pull only from one post

I’m playing with a photo blog now that they have CMS for it. I’m really just figuring it out. I have a few different “posts” designed with 1-5 images in each (used the multi image field). I dropped the light box in per this tutorial ( Introducing dynamic CMS and Ecommerce galleries | Webflow web design). I noticed it pulls the images from all of separate blog posts and oddly the one with multiple images only shows one image. Do I need to create a separate CMS collection for each “post” that has multiple images so it only pulls from that one?

Any links to tutorials or guidance appreciated.