How to add a shortcut to open a new finder window to the Launchpad or dock
Copy this script to a new ScriptEditor document.  Then export it as an application.  

tell application "Finder"
    activate
    make new Finder window to path to downloads folder
end tell


Next, Open the “Get Info” window for the “Downloads” folder and also open the “Get Info” window for the new application you just exported. Select the icon of the downloads folder and “Edit/Copy” Select the icon of the new application and “”Edit/Paste”.



Drag your new application down to your dock and you are good to go.