The first thing to do is find a recipe that works for you. It is easy enough to find everything you need in Doha to make ginger bread. Here is a recipe I have used in the past.
Make sure when you roll out your dough to cut the house that you do not roll it too thin. If it is a bit thicker then it is less likely to break.
If you are hosting a party go for smaller houses like the ones shown here. We use a template from Martha Stewart for the pattern. Print it on paper, cut it out and then lay it on your dough and use a pizza cutter to cut it out. You can find the template here.
You can buy the royal icing they talk about on the template here in Doha. Just check on the icing sugar packet that it says Royal Icing and follow the instructions on the packet to make it and then you should be good to go. You can get the disposable piping bags from Daiso at Hyatt Plaza.
The houses can be made in advance and kept until you need them. They will make your house smell divine! And of course the other option is to get Mega Bite Catering to do all the hard work for you. If you are going to order from them make sure you give them plenty of notice.