I have a brilliant book Godot 4.6 Game Development for Beginners by Wells Hayman * - but as I get to Page 20 I am asked to open my main.tscn but nowhere in the previous pages am I asked to save_as or to rename anything main.tscn. Sorry a real beginner question! I’m stuck on Page 20. With enormous thanks to anyone who can answer this!
We don’t own that book unfortunately, so we don’t know the full context.
What I can recommend though is that you finish this tutorial series first and then come back to your book, it should become clearer what the author had in mind.
Hate to say it but looking into your book it seems partially or mostly AI-Generated. Much of the code samples are quite bad and don’t follow Godot standard practices. It would make sense if it’s hard to follow just 20 pages in, as @wchc linked I’d highly recommend following the official docs which are up to date, great, and free.
If there is some scene you have for example placed a player character and coins or whatever in, it should be the main scene he refers to. The player itself would be an instance of the player scene and the coins instances of the coin scene.
Very many thanks for your replies - off to the official Godot tutorials!