I don't know where to add about elastic-apm module

Elastic Observability APM
1

about the flow where to add ? it about bin/elasticsearch file?
Then configure the elastic-apm module inside your application by adding the following lines to the very top of your application code:

// Add this to the VERY top of the first file loaded in your app
var apm = require('elastic-apm').start({
// Set required app name (allowed characters: a-z, A-Z, 0-9, -, _, and space)
appName: '',

// Set custom APM Server URL (default: http://localhost:8200)
serverUrl: ''
})

2

This code snippet is supposed to be added to the application you are monitoring. In you case it looks like you're monitoring a Node.js application. You need to add the "elastic-apm" npm module as a dependency to your Node.js application and add this snippet to the top of your Node.js application source code.