How to connect ELK to Gateway service (I have netflix Zuul) and collect logs of all microservices?

Question

Spring

Our microservice architecture consists of 25 services (Spring Boot), logs from which I need to collect.
I used to work only with monoliths, so I don’t know yet how to connect this stack and set up collection from all services.
ElasticSearch connected to one of the services to implement business logic, I use its cluster through bonsai.io. The services themselves are deployed through Heroku, we do not create containers manually.
I need to somehow collect logs with information about each request and response for each service (so that I can display the "routes" of each request throughout the web and the codes at each stage somewhere).
I rummaged through a car of information, everywhere they write that they use the Elastic-Logstash-Kibana stack, but for my case I don’t see specific tutorials on connecting (literally: what to add where in services and in Gateway).

Thank you!!!