The problem is most people think they can fit the tint to the glass straight from the roll, which never works.
If you do give it a go you'll need to lay the tint on the outside of the glass (clean the windows first) & gently heat it so that it takes the shape of the curve etc. Cut it to size (or as near as) then peel it off & fit it so the inside of the glass (clean side of the film that hasn't touched the outside of the glass), then start working bubbles in the water/sticking solution outwards to the edges of the glass with a soft aquifer or sponge. It may take 24hrs or so but tiny pin size bubbles evaporate & disappear.
Good luck, its not a nice job!