You seem to be very new to Katalon Studio.
The first thing you need to learn is how to open Browser, hot to navigate to the URL, how open tabs, how to select the phone number, how to get the text and save it into a variable. ---- All of these are the basic of Katalon Studio. To start with, see https://docs.katalon.com/katalon-studio/docs/quick_start.html or any other materials. You need to learn all of these step by step. Do not think you can get them through very quickly. You would need days or weeks. Stay calm and devote enough of your time.
As for writing data from Katalon Studio into Excel, the Excel Keywords is available. This would make your coding much easier.
Have a look at the following sample code of writing data int Excel workbook.