I want to make my Alexa says (You received a message from “sender name”) when someone messages me on WhatsApp and make my Alexa says (Receiving call from “caller name”) and repeat each 5 seconds till I answer the WhatsApp call and make a alarm bips on these 5 seconds interval
I’m beginning from scratch, I have just installed my Home Assistant and I literally know nothing
Shelve that one for the moment and try something simpler. 
Edit: A quick search of the forum and the docs (have you done that??) shows a couple of custom integrations available via HACS, but they seem to be mainly for sending WhatsApp notifications. It sounds as if it’s a bigger problem than you think. Using Alexa adds a extra layer of complexity. Isn’t there an Alexa skill or something?
Welcome to the forum, by the way!