Someone suggested when dragging folder, hold down the Option key and drag. I find no different without holding down Option, just that I don't see the Plus Green sign. What is the purpose?
But, what you stated indicates that you did notice a difference! Perhaps you know, but the green circle with the + in it means the action is a Copy. If there is no green/+ then it is a Move.
Since you've posted "newbie"/switcher questions, I'll share my standard "Tips"...
Tips for new Mac users:
You cannot cut and paste files in the Finder as you can in Explorer. To move or copy a file from one place to another, the Mac way is to open both the Target and Source folders, then drag and drop the file or folder. There are nuances depending on where the Target folder is. For example, hold down Option while dragging a file to copy it to a folder on the same volume.
The green button at the top does not expand the window to fill your screen. Very few windows need the full screen, so what that does is expand the window so it's large enough to handle the content. This will almost always leave some background visible.
The red button does not usually quit an application. It merely closes the active window, even if there's only one. The "light" by the application's icon in the Dock will indicate if the app is still running.
You cannot see the size of a file or folder in Icon View by holding your mouse over it. You must highlight the item and use Get Info. Or you can use List View, which will show you the size. There are at least four ways to access Get Info, three of them involving the mouse.
If you have two folders with the same name, but have a few differences between the contents of same, don't move one to the enclosing folder of the other. OSX will not automatically merge the contents of the two folders. Instead, it will overwrite the target folder with the one you're moving. The differences in the target folder will be lost forever. You will be prompted to confirm that you want to overwrite. Be sure you know what that means before saying yes!
You really don't need anti-virus software. It will just slow your computer down, and there isn't a single virus out there that will infect a Mac. If you run Windows on your Mac, you do have to take precautions for that. And, you can pass a virus on to a Windows user. Just be smart about where you go online and you'll be fine. It's also not necessary to run a defrag program. The Mac OS takes care of that for you. Some Mac users still do it, myself included, but you'll be fine without it.
You cannot selectively delete items that you have "stored" in the Trash. Sorry.
