Book 1 is a 4-card scene, Book 2 is a 6-card scene, and Book 3 will be a 9-card scene, befitting of the series finale
The definition is personal, but its a crucial first step
Credits are obtained by getting duplicate cards, and are used to buy any specific card
This is very different from, lets say, custom alter cards, as the art on those is the property of the people who make them, and also, you know you arent buying a real card. Play it safe if you print the back of an MTG card and put a custom-altered version on the front, and restrict its use to kitchen table rules
Creatures as large as 4/4 do not tend to be free, but about half the time Myr Enforcer comes down free of charge
You usually use this to target Kiki-Jiki, which you can then use to make a copy of Resto