I am going to assume you already know what http tunnels are for, and also ngrok.
1
Multiple ways to get to this tab, including the tower icon bottom left or good old cmd+shift+p

2
Choose your port of choice, and sign in through MS/GitHub. Very self-explanatory.

3
Change visibility to public, and optionally change protocol to https if requied.

4
This dialog box shows up the first time you access the tunnel link. And that's about that.

And et voilĂ ! We have a free ngrok alternative right within our beloved Visual Studio Code!