The self tint stuff goes on the inside mate. I did it on my old gen7 celica on the rear side windows.
I took the panels off inside, cut the film to roughly the right size (couple of inches bigger than needed) then stuck it as per instructions. Once it had dried, took a stanley to the edges to tidy it up, replaced the plastics, job done.
The rear window however, is a bit different.
You will struggle to find tinting film from a place like halfords that will cover the whole window in one piece. This obviously means there will need to be a join at some point, which if not married up well, will be really obvious, and look tits. (If you go for this, I advise putting the join vertically down the centre of the window, following the vertical heater element, to aid in hiding the join)
If I am correct, I think professionals use either film, or I believe they may use a spray tint? Not 100% sure.