@roundcork - two things. Which series are you actually doing? EPIC Beginnersquickly is only about 5 workouts, not 15, and it is meant to familiarize you with all the different moves. If you are not familiar with working out with dumbbells it is a good idea to do the Beginners until you feel totally comfortable.
Weights: far too light. 1 and 3kg is what you'd use for HIIT and other cardio type workouts that use weights. I started out with 3 and 5kg and moved up to 8, 10 and 12kg - initially fairly quickly, but much more gradually after a year or two.
Important to work on your core too - planks and abs work - as it makes lifting so much easier.