Retrieve info for specific user's ID

I do my PHD work dedicated to Social Network Analysis. As tools was selected Node JS and Facebook API Now what I can do is retrieve user's ID's with the additional info, but to build graph I need lists of the user's friends. I have Heroku App but I'm totally disappointed what to do with te APP_ID to get information needed to build data. Where I should start?

There are some Node.js packages available for this purpose.

Third party SDKs for Facebook

This is very useful, in case you want to write the same code and share between your server (nodejs) and the client (FB JS-SDK)

In order to start, you need to have access_tokens from users, you want information from. (Through FB App) 

FB.login(function(response) {
    if (response.authResponse) {
        var res = response.authResponse;
        FB.api('/me', function(response) {
          registerUser({ "fb_user_id": res.userID,      //register user in your database
                         "access_token": res.accessToken
                       }, function() {
              //handle here after registration
          });
        });
    } else {
        //handle reject in requested fields
    }
},  { scope: 'email,friends_about_me'});
//you can set scope field according to your use.

Refer to this for extended profile properties that can be used in scope field.

Once you get access_tokens, you can use them with one of the third party SDK above.

For example with facebook-node-sdk,

This sdk also provides you request access_token api

var FB = require('fb');
var accessToken = FB.getAccessToken();
FB.setAccessToken(accessToken);

FB.api('idHere', { fields: ['id', 'name'] }, function (res) {     //you can access fields, access_token has access to
  if(!res || res.error) {
    console.log(!res ? 'error occurred' : res.error);
    return;
  }
  console.log(res.id);
  console.log(res.name);
});

You can also use api function directly with access_token.

FB.api('me', { fields: ['id', 'name'], access_token: 'access_token' }, function (res) {
    console.log(res);
}