Add a VSCode walkthrough

[will-v-pi]

Add a walkthrough for users, to show the functionality of the extension (https://code.visualstudio.com/api/references/contribution-points#contributes.walkthroughs). This should include:

• Description of the extension and it's purpose
• Install instructions if on macOS (xcode-select --install)
• Which button to click for a new project/example
• The need to install the recommended extensions for debugging
• What settings are useful to change (eg features, correct debugger)
• How to connect the debugger (documentation links, or just diagrams)
• Which buttons to click for build & debug

[kaycebasques]

Seems like you can close this now that the extension is covered in the main flow of getting started with pico?

[neonmik]

There's still definitely more to be done here. Why is it downing python when I already have an up to date version? I know I need to specify the path, but that's not clear to a beginner.

[paulober]

Thanks for your feedback.

Why is it downloading python when I already have an up to date version?

Because custom Python installations from users have caused too many issues in the past, so they can't be trusted anymore by default.
If you want to use your system python, you can select "Use system version" under Python in the project generator after toggling "Advanced options" at the bottom.

There's still definitely more to be done here.

Could you please elaborate a bit more on what specifically need further work?

I know I need to specify the path, but that's not clear to a beginner.

It is explained in the README and a beginner would probably prefer having the extension taking care of the Python installation which requires no extra configuration.