What is the difference between the folders: 'All Photos' and 'Photos' - that's just for starters!

1 - they are not folders - in Photos exactly like iPhoto folders do not hold photos - they only hold albums or other folders

2 - both are standard system albums - Photos displays photos that are not hidden in photo date sort (Years/collections/moments) and all photos shows all photos sorted by date added to Photos

3 - Last import also is not a folder - it is a special system album which shows the last photos imported - they do not go anywhere - when you import again the new last import is shown

4 - You do not "place" Photos in albums and they do not go any place in that you never move anything in Photos (or iPhoto) - all photos are always in the library and you view them through various methods including albums (used for organization), All Photos, Photos and possibly other system albums

LN

#1 - The Photos window is mode where all of the photos are sorted by the date they were taken and grouped by date and location. It is only sorted by date with the oldest first (or at the top of the window).

The All Photos window is a mode where the photos are sorted by the date added to the library with the newest photos at the bottom of the window. It's sort order cannot be changed.

These two windows/modes are the basic viewing options for a Photos library.

Then there are folders which can hold other folders and albums but not photos themselves. Albums are used to hold/group photos.

#2 - once imported the photos stay where they are, i.e. in the Photos and All Photos window. If you want to group them separately in an album you can do so and the album will be easily accessible in the sidebar.

Moments in Photos are the new Events, i.e. groupings of photos sorted by date taken.

When the iPhoto Library was first migrated to Photos there is a folder created in the sidebar titled iPhoto Events and all migrated iPhoto Events (which are now Moments) are represented by an album in that folder.

To open the sidebar if it's not already open use the Option+Command+S key combination.

NOTE: It's been reported by several users that if the Event albums are moved out of the iPhoto Library folder in the sidebar they may disappear. It's not widespread but several users have reported that issue. Therefore, if you want to assure that you keep those Event albums don't move them outside the iPhoto Events folder.

There's a way to simulate events in Photos.

When new photos are imported into the Photos library go to the Last Import smart album, select all the photos and use the File ➙ New Album menu option or use the key combination Command+N. Name it as desired. It will appear just above the iPhoto Events folder where you can drag it into the iPhoto Events folder

When you click on the iPhoto Events folder you'll get a simulated iPhoto Events window.

Albums and smart albums can be sorted by Title, by Date with oldest first and by Date with newest first.

Tell Apple what missing features you'd like restored or new features added in Photos via Apple-Photos Feedback.