No problem at all Colin with the questions. Thats how we all roll here. Ask away here anytime.
Regarding advice to newcomers, it does depend somewhat on your background, your personality/motivations, and of course your goals.
You seem to have a similar background to me prior to Justin. I came in knowing a handful of open chords reasonably well, and tried to learn songs and fill in the gaps with stuff I didnt know. Endless frustration, and the reason Iād only last a few months, then give it away for a few years. Rinse and repeat. Not exactly a great formula 
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I started with Justin at the absolute beginning. Module 1, Lesson 1 - the rationale being to rectify basic technique problems, and fill in the many gaps in basic knowledge. I think this is the best starting point for anyone joining Justin Guitar.
I also started Justins Practical Music Theory course after a couple of months. Absolutely brilliant course, which Iāll be doing for life pretty much. Intensely practical in nature, and directly related to guitar. The pinnacle of Justins teaching I believe. I suppose it depends on ones situation, time constraints, motivations etc, as to when/ if to follow this path, but for me it has been the game changer. It is a paid course, but the cost is ridiculously low; the benefits enormous.
I also did Justins Strumming Techniques 1&2, also a paid course, but at about $10, its basically a robbery.. Exceptional course, with video and worksheets - it completely transformed my strumming and rhythm over a few months. If thereās one thing Iāve learnt in the last 2 years, its that rhythm in music is king.
Cant really comment on the App, as it came about fairly recently, and have never used it. It seems to be very good though, from reading in the forums. I believe thereās a 7 day trial. Perhaps try it out, and see if it fits your needs.
Developing a practice routine and setting goals is a critical aspect. Justin guides you through this in the early stages, and this sets you up well for developing your own as you move forward from the beginner courses.
Join in the community forums. I made the mistake of lurking around the edges for much of the first year, being a naturally introverted type. Really joining in, being vulnerable, asking questions, posting videos etc has helped significantly in my development and confidence. I suppose different personality types handle this in various ways. This community really is one if those special places, full of tremendously giving people of all levels.
Above all, follow Justins tuition and advice, and always ask questions about the why where needed. I believe if its reconciled in your mind, then the pathway to the fretboard will flow much better.
Now, there are many, many here vastly more experienced and talented than me. Im grateful for that, as hanging around better players helps me. Iām still relatively very early on in this journey, but the above is what has worked for me so far, and is a completely different ballgame to my previous fumbled attempts at learning guitar.
Hope this helps somewhat. Others will likely chime in here with some more sage advice.
Cheers, Shane 
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