Just for everyone's information, since the startup folder is difficult to find, The Windows key and R (win-r) brings up a run command window. Then shell:startup opens file explorer directly in the startup folder. Much easier than walking there.
For the record, the shell:startup thing is only supported in newer versions of Windows. A more universal yet username-agnostic method is to copy and paste %APPDATA%\Microsoft\Windows\Start Menu\Programs\Startup into the address bar in Windows Explorer and press Enter.