It looks like you might have overwritten the index.html file with one generated using the UI Builder (the generated index.html uses resources array with Resource 1 and Resource 2 defined).
If you download the project zip using the "Download Now" link at the top of the article (TutorialHtml5Machines.Php.20180131.zip) you'll get a ready-to-run project. In order to switch to MySQL, it's only necessary to edit _db.php and _db_mysql.php (as you did). You don't need to follow all the implementation steps described in the tutorial (it contains the final implementation).
The db will be created and initialized automatically (give the permissions are correct). You should see a tree with "Cutting", "Welding" and "Sandblasting" groups on the left.
Please let me know if it still doesn't work.