These tutorials are supposed to give a whirlwind introduction to building and running agents in jade (with the help of Protégé). Jade is a large system which does lots, these tutorials over what I think you need to understand for your courswork and not more. There is weath of documentation on these and other aspects of jade on the Jade homepage and elsewhere on the web.
IMPORTANT: The agents in these tutorials are written using behaviours. For the coursework, you should not use jade behaviours in your agent and should use drools instead. However, these tutorials are still very useful for learning how to do things such as send messages, use the DF, etc.
Instead of using behaviours, the starter agents that you are given already run one behaviour, the CyclicDroolsBehaviour, which takes all incoming messages and asserts them into the working memory of the drools engine. Your .drl files for the supplier and client agents should contain rules that define how your agent should act when these messages are received.