A tag or collection dropped onto an unselected photo applies to that photo only, even if other photos are selected. If you have multiple images selected and drop a tag on one of them, that tag applies to all the selected images.
Creating collections and groups for each page or spread sounds like a lot of work. It's not absolutely necessary, but because you cannot safely edit images that are included in an album without jeopardizing the album, it's a good idea. These collections facilitate the process of editing images that appear together. If you're not used to working with photos on spreads, consider your first few albums warm ups for getting the hang of how photos can work together.
search with tags p. 20
To exclude categories or tags from a search, right-click the check box and choose Exclude Photos with . . . from the menu.