Beginner level sewer's question here... so if I want to have simple 20inch deep, 2inch tall and 45inch wide bench cushions in this box style without piping or fancy trims, but which way do I lay out my fabric in order to cut? Bottom and boxing on selvege or??? This pattern is perfect for what I'm trying to do but I'm not sure where to start with the first step! Anyone please advise? THANK YOU!!!