Take a look at the toolpaths. He did a Vcarve on the letters with a 60° Vbit. The width of the letters determines the depth of the cut. Hover over the toolpath name and you will see the max cut depth. The connecting lines are at a flat depth of 0.05 'on the line' with the same vbit. The holes are defined as 0.24, and are cut with an inside profile with a 1/8" bit.
I highly recommend that you watch some of the beginner tutorials (then watch the rest). I guarantee that they will save you much grief and wasted time.