Hi! Thanks for taking an interest in my app!
I suspect you're using Godot 4 which is why you're getting those deprecation issues.
You need to use the specific version of godot outlined in the tutorial. It does provide a link to the specific versions archive. (Should be approx. 3.5.x if I remember correctly)
Since I've left this one out in the cold for a while I'm going to bring it up-to-spec with my newer apps and port it over to godot 4 starting in the new year.
Hopefully I've solved your issue but do reach out if you have any other questions :)