Copy the variables (%xxxx%) into the windows explorer address bar and hit enter.
%AppData% - "C:\Users\{username}\AppData\Roaming"
%ALLUSERSPROFILE% or %PROGRAMDATA% - "C:\ProgramData"
%CommonProgramFiles(x86)% or %CommonProgramW6432% - "C:\Program Files (x86)\Common Files"
%LOCALAPPDATA% - "C:\Users\{username}\AppData\Local"
%OneDrive% - access your OneDrive folder
%ProgramFiles% - "C:\Program Files"
%SystemRoot% - "C:\Windows"
%TEMP% or \%TMP\% - "C:\Users\{username}\AppData\Local\Temp"
%SystemDrive% - "C:\"
%USERPROFILE% - "C:\Users\{username}"
%windir% - "C:\Windows"
There are other environmental variables, but the ones listed above are the most common I remembered from the top of my head.
For more examples and more information about environmental variables, check this out.
Additional:
I recently found out that shell can also open folder locations.
Typing "Shell:Startup" to the windows explorer address bar opens up the start up folder. You can paste a link or any executables here and it will run on windows startup.