How do I set system environment variables in Windows 10?

Question

How do I set a system environment variable in Windows 10 (without using the registry editor)?(Note: Other answers don't specifically address Windows 10 - at least not yet - and they leave off important steps - like how to open the control panel - that changed since previous versions of Windows.)

Answer 1

1. Hit the "start" icon
2. Hit the "settings" icon (looks like a gear)
3. In the "find a setting" box, type 'env' -- this gives a popup with two choices
4. Click on one of the two choices, for example "Edit the environment variables for your account" -- this may appear to do nothing, since Windows 10 hides the edit window behind the Settings window
5. Close the system window that is hiding the Environment Variables window
6. The Environment Variables window has two sets of 'New', 'Edit', and 'Delete' buttons. Only one set will be active, depending on the choice you made in Step 4 (You need to be an administrator to change the System variables)
7. Use the active buttons
8. New opens a popup with the variable name and value
9. For Edit, highlight the variable you want to modify and then click the button. This opens a popup with the name and value of the selected variable.
10. Delete removes the highlighted variable. Do not remove any of the default environment variables; you can cause serious problems.
11. Use the Cancel button on the bottom of the Environment Variables window if you make an error that you cannot undo.
12. Use the Save button on the bottom of the Environment Variables window when you are satisfied with your changes.