adding comment on how to generate proto classes

order-redirect/php/ActionFeedExample.php

diff --git a/order-redirect/php/ActionFeedExample.php b/order-redirect/php/ActionFeedExample.php
index 83558d2..a0d5fdf 100644
--- a/order-redirect/php/ActionFeedExample.php
+++ b/order-redirect/php/ActionFeedExample.php
@@ -1,6 +1,9 @@
 <?php
 /*
-Example Action feed for Google Order Redirect.
+Example Action feed for Google Order Redirect. Create build/gen directory for generated proto classes.
+Download lastest version of protoc from https://github.com/protocolbuffers/protobuf/releases
+Generate proto classes with:
+protoc --php_out=./build/gen --proto_path=../proto/ ../proto/*.proto ../proto/google/type/*.proto
 */
 
 require dirname(__FILE__).'/vendor/autoload.php';

order-redirect/php/EntityFeedExample.php

diff --git a/order-redirect/php/EntityFeedExample.php b/order-redirect/php/EntityFeedExample.php
index 13c748b..dc32d4b 100644
--- a/order-redirect/php/EntityFeedExample.php
+++ b/order-redirect/php/EntityFeedExample.php
@@ -1,6 +1,9 @@
 <?php
 /*
-Example Entity feed for Google Order Redirect.
+Example Entity feed for Google Order Redirect. Create build/gen directory for generated proto classes.
+Download lastest version of protoc from https://github.com/protocolbuffers/protobuf/releases
+Generate proto classes with:
+protoc --php_out=./build/gen --proto_path=../proto/ ../proto/*.proto ../proto/google/type/*.proto
 */
 
 require dirname(__FILE__).'/vendor/autoload.php';