The principal adores his grandson very much and asks the Sket-dan to prepare a picture play to entertain him. They decide to base the story off of Momotaro, but change things up from the usual... Afterwards, he asks them to play with his grandson for an afternoon, but the kid doesn't seem interested in having fun at all.
Once you get a certain level of 
know-how and understand the theory,
Una vez que te familiarizas 
con la mecánica del juego,
Una vez que te familiarizas 
con la mecánica del juego,
Depois que você entende um pouco
 de seu funcionamento e teoria,