When you first open Visual Studio Code, you’ll see the Explorer window is divided into two subpanels: Open Editors and No Folder Opened.
The Open Editors subpanel shows any files that are currently open in Visual Studio Code. And right now, under No Folder Opened, the only option is to click the button Open Folder. This allows you to select a folder as a working folder. It will then display all the folders and files located in that folder.
This makes it easy to access all the files and subfolders in this main folder, without having to switch back and forth between Windows Explorer.