Someone else may have already mentioned this, but it looks like the "Getting Started with AGS" tutorial in the online manual is more current than the one posted directly to the website.
The website one appears to be designed for AGS 3.0 and was last updated in 2007, while the one in the manual is being updated for AGS 3.5. The content in both are very similar, but there are some differences in the default settings and UI that make the older one a bit more difficult to follow:
- First section of website tutorial: https://www.adventuregamestudio.co.uk/site/ags/tutorial/ags/1/
- First section of manual tutorial: https://adventuregamestudio.github.io/ags-manual/acintro1.html
@PAsystem , AGS is more a community effort without some central authority, so things don't always go together in-hand, the website I believe gets more usage for the Forums, the Games DB and some extra functionality (game of the month, awards, ...). There is a redesign in the works that will eventually be done.
In the meantime, the manual on GitHub is the more recent one as you noticed, but if you are using the AGS Editor, you can read it directly by hitting F1, as it's the same manual that is integrated in the Editor. It will also work offline as an added benefit for being packaged with the Editor. :)