title: How to show personalized 'Welcome Message' in facebook messenger?
body: <p>I would like to show 'welcome message' like 'Hi Robert, welcome to my application'.
  So I need to send:</p>
  
  <ol>
  <li><p>"<a href="https://graph.facebook.com/v2.6/USER_ID?fields=first_name,last_name,profile_pic,locale,timezone,gender&amp;access_token=PAGE_ACCESS_TOKEN" rel="nofollow">https://graph.facebook.com/v2.6/USER_ID?fields=first_name,last_name,profile_pic,locale,timezone,gender&amp;access_token=PAGE_ACCESS_TOKEN</a>"</p></li>
  <li><p>using 'first_name' from 1st request, send "<a href="https://graph.facebook.com/v2.6/PAGE_ID/thread_settings?access_token=PAGE_ACCESS_TOKEN" rel="nofollow">https://graph.facebook.com/v2.6/PAGE_ID/thread_settings?access_token=PAGE_ACCESS_TOKEN</a>" request to set 'welcome message'.</p></li>
  </ol>
  
  <p>However, I need to know user_id before first request.</p>
  
  <p>My questions: </p>
  
  <ol>
  <li>What are steps to create 'Welcome message'?</li>
  <li>How to show 'Welcome message', when user opened facebook messenger window?</li>
  </ol>
  
  <p>I reviewed <a href="https://developers.facebook.com/docs/messenger-platform" rel="nofollow">https://developers.facebook.com/docs/messenger-platform</a> document, and I have still questions.</p>