Lightroom - How To Create Collections

Collections: Collections are a way of creating logical groupings of images from different folders. A single image from one of your folders can even sit in multiple Collections if you want it to. After creating a collection, you can then drop single or multiple images into the Collection from your Folders.

Smart Collection: A Smart Collection is just the same as a standard Collection, it is a logical grouping of images from your Folders. The difference with Smart Collections is that you automatically collect images from your Folders based on tags. An example is if you want to collect all of your images with a specific person in them, Smart Collections can do that for you.

Collection Sets: A Collection Set is a collection of Collections. Lightroom even allows you to create a Collection Set within another Collection Set. So basically, you can use Collection Sets to create nested Collections.

Step 1 - From the Collection panel, select the + icon at the top-right of the panel.

Step 2 - You then have the option of creating a Collection, Collection Set or Smart Collection. 

If you are creating a Collection Set, you just follow the onscreen prompts and give your Collection Set a name. You can then create Collections inside of it using the same Steps 1 and 2

If you are creating a Collection, you follow the on-screen prompts and give your Collection a name. You can then drag and drop images into the Collection from any of your folders. If you want to delete a photo from a Collection, you just select it and press Delete. This deletes it from the Collection but not the Library.

If you are creating a Smart Collection, you start with a name and then create match criteria using the rules. These create groups of images based on your criteria. So, in this example, I called my Smart Collection 'Otters', and then populated it with images that were flagged, and contained the exact keyword otter.