So what do I make of these 16 digits? What is the significance of the zeroes, the x, and the singular letter?
Err, that's the notation of a hex number. If you're asking this question, then clearly, this is not a Kutto thing to be doing.
"Expressions" are basically your generic assignment/comparison statement. The "expression" opcode, 0x02, basically does the simple scutwork of variable and constant (both TS2 "constants" and literal constants) manipulation. Setting things equal to each other, comparing things, adding things, subtracting things, etc.