CTRL+SHIFT+P
will bring up the command palette.
Depending on what you're running of course. Example in an ASP.net app you can type in:
>kestrel
and then open up your web browser and type in localhost:(your port here)
.
If you type in >
it will show you the show and run commands
Or in your case with HTML, I think F5
after opening the command palette should open the debugger.
Source: link