FULL TUTORIAL: https://photography.tutsplus.com/tutorials/all-about-adobe-lightroom-stacks--cms-25745?utm_campaign=yt_tutsplus_HO1ab4LtLek&utm_medium=referral&utm_source=youtube.com&utm_content=description
Stacks are all about tidying up your view in Adobe Lightroom. When you have a series of images that are really similar, it often makes sense to combine them into a single stack.
Think of stacking images as taking all of the playing cards on a table, and neatly stacking them into a deck. Stacking images doesn't alter the original files—it only changes the way that they display in Lightroom. We can stack lots of images onto a single tile so that our Lightroom catalog is much neater.