Hi Toverway and welcome to the site! To exchange email with another WhatNexter, just go to their home page by clicking on their user name that is highlighted, when you get to their home page you will see a link on the top of the page at the right that says "exchange email". Click that, they will be sent an email notification that you wish to exchange emails. If they agree, they can then email you back using the link that is sent to them.
Let me know if you have any other questions, I am happy to help. I hope your journey with Thyroid Cancer is going OK.