Week two just increases your jog & walk times by 30 seconds. It's a very gradual approach, but it's not a bad idea to repeat a week if you don't feel comfortable moving on. The important thing is that you're doing it. Good job!
Try to establish a rhythm with your breaths / steps. For example inhale for two steps & exhale for two steps. I personally inhale for three & exhale for two. It's a pretty common cadence for runners. Once you get comfortable with the rhythm & you're not concentrating on the breathing you will start to enjoy the run more. Just for the record stop breathing through your nose. You will get a lot more air in with your mouth which is what you need while exercising!