changing to Photos from iPhotos

Right. Your albums in iPhoto will be carried over with no changes. Events no longer exist in Photos so they will be converted into albums. Any album in Photos can be edited regardless of where it came from. You can rearrange, add, or remove items; and organize the albums into whatever folder structure you prefer.

It's only the AI-generated Memories that cannot be edited. This feature did not exist in iPhoto.

Here is a support document that highlights some common places to look for things that got moved during the upgrade: https://support.apple.com/en-us/HT204887

I have been working on my events. I have combined a lot of events , so the dates are off sometimes. ( I have a lot of random photos that i added to events). I gave the events Title names plus a month/year. I plan to move events to albums . Using sub folders to separate events . (For instance: Boy Scouts 2005, Boy Scouts 2006, etc) the overall Album name will be Boy Scouts.

Photos 5 on Catalina does not have events.

When you migrate your iPhoto Library to Photos, the iPhoto events will be automatically replaced by albums named like the event. The new albums will appear in Photos in a folder named "iPhoto Events". If the events have been in sub folders, you will find the same subfolders in Photos. The descriptions you added to your events or albums will be missing, because Photos does not support descriptions for albums. Any subscriptions for albums or events should be saved as a description of one of the photos in the event.

I read that photos can only be in one event. But I have the same photo in more than one event. Will they still be together like I have them in the Albums? After I go to the new Photos App Or will some disappear ?

If you have the same photo in different iPhoto events, you may have duplicated the photo or imported it twice and you will find it twice in Photos as well.

What does AL memories mean?

Phillip has been taking about AI (Artificial Intelligence) generated memories. It is a nuisance that the font on this web page does not make a difference between the lower case letter "l" and the upper case letter "I", unless we are using the code block format.

Memories are created automatically by Photos. The Photos.app is scanning your Photos Library, and occasionally it will present a collection of photos you have not looked at for a long time - photos of a special event, a special location, of a special person.

I collected a few recommendations on how to prepare an iPhoto Library before migrating to Photos. It will be best done while still running Mojave, see: Notes on Migrating an iPhoto Library from iPhoto to Photos for Mac

The album titles will be migrated to photos. See this document on how the items from iPhoto will be migrated to Photos: How Photos handles content and metadata from iPhoto and Aperture - Apple Support

You will be able to edit and adjust your photos after the migration to Photos like before in iPhoto.

There is one exception - if you already edited a photo in iPhoto, you cannot add further adjustments in Photos. You will have to revert the photo to the original and start over, before you can touch it up in Photos. The editing tools are slightly different in Photos, so Photos cannot recreate the iPhoto adjustments.

Here is the current user guide for Photos: Photos User Guide for Mac - Apple Support

1) You have the ability to edit the contents of an album as well as create and delete new albums. You can add, remove and rearrange the order of items in your albums.

There are also smart albums - they existed in iPhoto as well - that allow you to create automatic albums based on criteria that you choose.

Memories, on the other hand, are not editable. You can favorite, delete or block a memory but you can't edit the photos in one by adding or removing specific ones. And, don't try deleting a photo from a memory because you'll learn the hard way that it deletes it from your library.

2) You can always access all of your photos in the Photos section of the library. There's literally a tab at the top labeled All Photos. You can also view them in a condensed timeline by years, months or days. Nothing will happen to your photos that aren't part of an event. Just like iPhoto, you don't need to put your stuff in albums. That's just for people who want that extra layer of organization in their photo library.

This is completely unrelated to Photos but I can help.

The Macintosh HD icon is the icon that represents the contents of your hard drive. You can hide it if you don't want to see it on your desktop. Go to Finder > Preferences and turn off the Hard disks option on the General tab. At least that's how it works on current versions of Mac OS. It may have been a bit different on Yosemite but I can't recall. Probably the same.

As for your downloads folder, like any folder on your computer, why keep stuff you don't need? It really won't affect much of anything to keep things in there but if you leave stuff sitting around that you don't need then your hard drive will fill up.

I'm not sure what you've read that "you may need some things on it?" Can you elaborate?

Removing items from an album does not delete them from my recollection of using iPhoto. Your photos do not need to all be in albums from a technical perspective.