To search for photos in selected folders and their subfolders, use Organize | Search…
This window divides the search conditions you can use into four types. The conditions are divided into tabs (sections). You can disable an entire tab at once using the checkbox by its name.
Note that search conditions in checkmarked tabs are used even if those tabs are not currently displayed!
You can search by filename, location, the picture file's time/date, the actual picture-taken time/date, file size, author, description, rating, and keywords. In the Advanced Search tab, you can also search by camera-related EXIF picture information (shutter, exposure time, ISO, exposure compensation, flash, focal length) and by similarity of color to a selected photograph. In the GPS tab, you can search by a geographical location. To set the location to search by, use the map or choose a picture whose coordinates the program will use. You can use conditions ("contains"/"does not contain") and logical operators (AND and OR) to modify searches for textual picture information.