Hi @DecoderDeep,
Thanks for your post and interest with this project. I think a good starting exercise will be think about what kind of experience you'll want the user to have and come up with ideas for that.
What will the user experience flow will look like - so what screens will the user see and how will they be guided through the initial steps. Will they just see code right away, or will there be some sort of a write up that comes first? What general topics will the tutorials cover? Will they be guided on which buttons to click/commands to run? For example, would it just be text, or would you have an arrow that pops up on VS Code somehow that says "Click this button here". Or would the button glow-up to allow the user to figure out what it is, and possibly also look into the APIs that could allow for this. You could do this with text or also try to do some mockups to get a feel for how things would look.
While doing so I would try to keep in mind that users who use this feature will probably be new to the language/extension (perhaps even VS Code), so they may not even know about DocC or Swift testing, for example, so you may need to have some way that explains what it is and how the extension can help you run it.
Also may be good to think about some general ideas on how to incorporate this into the VS Code extension. Will the tutorial content be hard-coded, or will it be auto generated somehow? We would want to ensure that the tutorial always works when called upon and that it is easy to update when the language/features changes.
In terms of implementation I think the Walkthrough mode and CodeTour extensions are good starting points, and there may be other extensions/tutorials you can look to as well. You can check out the VS Code marketplace or tutorials for other languages (or even things like vimtutor) and hopefully get some inspiration from them.
Hope this helps, and looking forward to see what ideas you come up with. It seems like you've already mentioned some in the previous post about this project which is great to see.