Webhooks and Alexa speaking message how?

Hi Guys,

I would like to send a webhook to Homeassistant. So that it then starts an action. Namely that Alexa speaks a message.

This is already working very well.
How do I get Alexa not to speak a predefined message? Instead, it speaks the message that is transmitted as a message in the webhook?

The background is I use a program: Tradingview and there I can also send a message via webhook. Then I wouldn’t have to make lots of different webhooks for different messages but can stay with one webhook and enter the info into the message box of Tradingview.

Any ideas?
thank you