How to configurate interaction between my own authentication server and Express-Gateway?

Question

I'm a new to microservice architecture. In general, we have an applictaion broken into microsrvices. I was advised to use API Gateway as a client request router. I chose the Express-Gateway. And that's what i want to do: I need that when unauthorized user sends a request, his request would be redirected to the authorization service. On the authorization service the SMS code would be validated and then a JWT would be generated. This token would be sent to the client and saved in the Express-Gateway system. In the future, Express-Gateway would check the token and, upon successful validation, redirect requests to other services. How can I implement such a solution, or are there other options? I just don't like Express-Gateway's Consumers Management System, and I need my own authentication logic.