How to execute a command

[minjungsung1994]

microsoft/vscode#91424

I am trying to export outline cpp file from vscode. When I looked it up, it seems like the issue code above is
explaining how by executing "vscode.executeDocumentSymbolProvider"

Yet, I have no idea where to execute it. Is it shell command? do I simply put that on command palette?
Assuming that I am a total newbie to VScode, could you explain a way to execute them with some screenshots or whatever?

Thanks!