There is now an in-game tutorial available at various locations. Once you start the game, you are asked if you want to read it and once you say no, the game starts normally (there is a bug, however, if you read it once: Your character will be able to attack once, probably due to RPG Maker event lag while multiple non-parallel-process events are launched at the same time. However, you still won't be able to kill the first enemies , so you'll obviously still need your attack upgrade.
Inside the tutorial, the girl with white hair and clothes will conclude by asking you to attack her, as a proof that you have RTFM ( @MateoConLechuga
would probably like that
The tutorial is also available by talking to the three
(other than the Walrii Express one) that are located in towns.