Postback Manager
In the menu Bot manager Automation Postback Manager , this generally displays the postbacks in all current Flows. Normally, we will not use this, but if you need to use it for Facebook click to messenger ads, then we need to get the Json Code here.

First we must create a new Flow for ADS, but make sure you have created the main Flow, which will be used for subsequent button postbacks.
In the Visual Flow Builder Editor, if you want to create a Facebook ads flow, there are some limitations
1. Only one message is allowed (can be paired with a button or quick reply)
2. For ads avoid putting first name, last name, direct link of webivew form, direct link of ecommerce store. These will not work.

To start the entire Flow when setting up the button you can use “Start a flow” and select the button of the previously created Flow as the postback.

After creating the ADS Flow, you can return to Bot manager Automation Postback Manager to see the name of the Flow you just created. You can click the icon in the figure to get the Json code

You can copy the json code and go to Facebook Ads Manager to set it up.

In Facebook Ads Manager, select “Partner app” in “Message template” and click Select flow

Next we click “Enter JSON Code”

We need to delete the default Json Code

Next we need to paste the JSON Code we just copied into it

If everything goes well, you will be able to see the ads flow you just created.

Next, click “Save” and you’re done. You can also click “Preview in Messenger” to test it.

You will then receive a test message from your Page in your Facebook account.