If you're in the US, you should be able to find stuff like this:
www.google.com/search?q=paper+faced+insulation&rlz=1C5CHFA_enUS615US615&espv=2&biw=1241&bih=906&source=lnms&tbm=isch&sa=X&ved=0ahUKEwj2v_r9u_DNAhVFJCYKHRPWC9EQ_AUICCgD#imgrc=l-jI8jneHIZ7QM%3AFor your front wall, Ethan said you could use all paper because it is not a reflection point so you can staple the paper to the frames. If you want to fill the space behind, you can also roll out unfaced insulation on the floor behind the wall... layer upon layer up to the ceiling, sure, the bottom layers will compress but only to a point, if you're worried about that, your can build in some kind of support every few feet or so or suspend them with twine from the ceiling...If you're going to DIY, you have to work with what you've got and experiment and improvise. I don't think anyone does this kind of thing exactly the same way.
Here's a link for insulation nails
www.google.com/search?q=insulation+nails&rlz=1C5CHFA_enUS615US615&espv=2&biw=1241&bih=906&source=lnms&tbm=isch&sa=X&ved=0ahUKEwj3sLL0wfDNAhWK7SYKHeiSCBgQ_AUIBygCI built a frame like I'm suggesting back in the 80's but it was flush against the existing wall and only 3.5" thick with mineral wool covered with burlap. I didn't know any better. With what I know today, I would do it differently, possibly something like I'm suggesting but I would be experimenting too, but I'd get it to work somehow and I'm sure you'll figure it out too.
Cheers
Rock
Thanks Rock. Yeah I fear you may be right but I am on a budget so can't really experiment too much without clear direction because If I make a mess it may cost me and it has in the past. I kinda want to know what materials to buy before so I can put together a shopping list.
I thought that many guys were doing this regularly and that there would be some solid info out there on how to do it but not so much. I will definitely share my experience when I set out to do it so others can benefit from it but I first need to be sure about how to proceed. So, I thought about using some kind of wire mesh and sticking the insulation on the mesh and then hanging the mesh to the studs but I don't know how I would attach the insulation to the mesh nor how to attach the mesh to the steel studs (see pic attached). Then another method that I have seen done is to create shelving. Just basically create three or four shelves and lay the insulation on the shelves horizontally. I think this last option is the only one that really poses no doubt in my mind but I would really prefer the insulation to be vertical instead of horizontal
Building flush against the existing wall surely is a lot easier than what I want to do leaving a gap. That is something I may have to consider