Using hugs

Hi, I have just downloaded the hugs which I intend to use to write demo programs for my my presentation. The problem is that I don,t really how to make full use of the graphical capabilities. Would you please sent me some information concerning this matter. I will be grateful if you also any demo programs that you thing will help me do a good presentation, I more than happy to accept. Do you have any manual, Test cases etc. Finally could you highlight any disadvantages of functional programming and any suggestiong to rectify thses problems. Thanks Emmanuel Berend Quarteyson