I've watched as many videos as I can find and already have my Starter Kit. One thing I'm really confused about is how to determine which side of board will be the inside of the box? As I understand it, you put the finger end in boiling water, after which, you'll see the board cup. The inside of the cup is the outside of the box. Now, at that point, you've already cut the fingers out, so haven't you had to already determine the inside/outside? Exactly what is the sequence of marking, cutting and inside/outside determination?