I NEED HELP with Kafka

I'm working a thesis. I developed 4 different microservices (REST APIs). I would like to use Kafka to support large number of users. I may also place the microservices behind a HAPI Proxy. How can I use Kafka to stream requests and respond accordingly. I'm using Node.js. I think I haven't grasped Kafka. My Prof, suggested I try it to act as a broker but I'm blank right now. How do I tell Kafka I want it do a POST or GET etc?