How to set welcome message for messanger chat bot build using AWS Lex

I built a chat bot for my project using AWS Lex and then I integrated it with Facebook Messenger. After integrating with Facebook Messenger my chatbot interface looked like this.

In the image you can see when some open the messenger he will get suggestions like "Where are you located?" or "What are your hours?" etc. by default.

Expected output: I want instead of these default suggestions messenger should display customized message like "Hello welcome".

You can create a customized greeting from your Page that will appear in Facebook messages and in the Messenger app for iPhone, iPad and Android when someone begins a conversation with your Page for the first time. Your Page's greeting will appear before any messages are sent. To create a Messenger greeting:

1. Click Settings at the top of your Page.
2. Click Messaging in the left column.
3. Next to Show a Messenger greeting, click to select On.
4. Click Change, edit the greeting, then click Save.