I think you need to be a little more specific about that. What exactly is the problem? Where do you get stuck?
Two ideas/questions from the top of my head: 1. Did you work your way through the getting started tutorials here in the tutorials sections? That covers a lot! 2. Write a game design document: What is the gameplay like? How do the gamemechanics work? etc. Then, starting with that you can begin coding/building step by step. If you get stuck, you can ask more specific questions here! ;o)
Just to add that party games are one of the most difficult type of game to design. You don't have to think about one game design, but several, and because of that creating a - good - party game is very time consuming and difficult. Your mini games have to be as good as other.