Windows 10 includes a new feature for Remote Assistance called "Quick Assist." It is aptly named; it is much easier and faster to use than Microsoft Remote Assistance (MSRA).
This article is written from the perspective of someone desiring assistance. The process for the person providing assistance is equally easy and requires no explanation; it's obvious. The easiest way to do Quick Assist remote sessions is by having a phone or Skype call at the same time.
The quickest way to start Quick Assist is to use a keyboard shortcut. Hold the Windows Key and the Control (Ctrl) key down, then press Q. In other words, Win + Ctrl + Q.
The easiest way to find Quick Assist is to search for it. This is done by pressing the Windows key on the keyboard and then typing "Quick Assist." There is no visible box in which to type; just start typing after pressing the Windows key.
Windows will display its normal menu stack for search results and Quick Assist will appear at the top. Be sure to look for the words "Desktop App" under the name. Don't select anything under Search Results in the menu stack. If you don't see the Desktop App entry, wait a few seconds or try again. If this is the first time you've ever searched for Quick Access, it may take a few seconds for Windows to get it.
Click the Desktop App entry for Quick Assist.
Quick Assist can also be found in the Windows menu under Windows Accessories, in which case you simply click that entry in the menu.
That's the most complicated part. Once you've got the app up and running everything else is crazy easy.
To get help, select Get Assistance from the Quick Assist window. The window will change to a dialog requesting a code. Your helper can tell you the code on the phone or can email it to you. After you enter the code, Quick Assist will ask you to confirm that you want to give the helper access and once you agree the helper will be able to see your screen.
After that, everything is very obvious.
This article was written some time ago. Since the original version, the presentation of the dialogs has changed a bit. The description of the process above is still entirely accurate.