With it being a new build, chances are it'll be 'dot & dab' fixed plasterboard (especially if it's on an outside or party wall). This is where the wall is made of lightwieght concrete blocks, and then the plasterboard is 'glued' to the concrete with a special adhesive.
What this means is that although the plasterboard sounds hollow when you knock on it, there's only a gap of around 5-15mm behind it - then there's the concrete blocks which you can get a solid fixing in.
Simply drill your fixing holes through the plasterboard and into the concrete (check if there's likely to be any cables in there first!). Then you can fit a frame fixing (this is just like a plastic wall plug, only longer to bridge the plasterboard/air gap) and screw the TV bracket on. Be careful you don't overtighten the screws, otherwise it'll pull the plasterboard further into the wall.
If it is a stud wall (unlikely, but there's always a chance) you can use plasterboard fixings. If you get the right ones, they'll easily take the weight of a 32" TV on a standard bracket. Alternatively if you're paranoid or using an extending bracket, your best bet would be to locate the studs, remove a section of plasterboard between two of them, and replace it with a piece of plywood of the same thickness screwed securely into the studwork. Then fix the bracket to this. This is the messiest aproach, and will require quite a bit of remedial work to get the wall looking good again.
Hope that helps, and makes sense - it's easy to do, but hard to describe in writing!!!
