How to get user phone in telegram

I need to build a flow where the user by sending the command /register gets a button. When he press it he send his phone number.

have you installed telegrambot
and
have you looked at
import > examples > telegrambot
in the editor

yes I did.
I am not able to build a button that. send me the phone number.

You will not get a phone number (unless the user sends you one manually) as that is private info, you identify people or chats with a chatid. If you look at examples there are examples of keyboard(buttons) and when they respond by clicking it, you will see a chatid, that you use to respond to the user that pressed the button

In the past i did it.
but I do not remember..
is was a button thats send the contact information

I foun this

but cant meke it work

Again install the https://flows.nodered.org/node/node-red-contrib-telegrambot the editor has woking examples for creating keyboards.