How do I link Drush to my Drupal site on Pantheon?
Start off by installing Terminus. Terminus now supports machine tokens; once you set these, up you can authenticate automatically without a password simply by running terminus auth login &lt;email address&gt;.

Once you are authenticated with Terminus, terminus sites aliases will download Drush aliases for all of your Pantheon sites. Since this list can change over time (e.g. when you add or delete sites on Pantheon), you will want to periodically re-run this command.  You might even want to have Terminus log in and update your aliases in your shell startup script (e.g. .bashrc).

Once your aliases are up-to-date, you can use a remote site via:

drush @pantheon.mysitename.dev status