How do you exactly debate in the Model UN?

Do you get to say stuff only regarding your country? I'm doing Somalia...am I allowed to go against my enemy country through my speeches and debates..and when they come up with resolutions, is it just one for each committee or one for each country? I don't really understand the speech part either...I'm in the General embly, the topics for discussion are as a weapon of war, global food crisis, and environmental sustainability