Advice with API / Microservice testing

I'm quite new to test automation and I need some advice in regards to a project I'm working on.

I am writing automation for an Angular 2 website with Protractor and I have been tasked to test the microservices behind it. I assume integration/component tests and checking response codes?

I am unfamiliar where to start, some of the microservices are also shared with an app (both written in C#).

I only have knowledge of JS, do I need to find a framework? I assume I will need to learn C# too. I've been using postman so far for firing requests, the first microservice is a CRUD service.

Apologies this is a bit vague, I'm a bit unsure about the topic.

Thanks!