Create the account (and set proper upstream)
If the client wants to use the standard drop-8 upstream for easy upgrading, you will need to collapse the acuqia file structure down so there is not a nested docroot.
If the client is sticking with a composer build, you can keep the nested docroot, and can create the site without an upstream:
Set up the pantheon.yml file
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The api_version line is standard. You can use drush status to get the php and drush versions of the current acquia site. Since there is a If you are sticking with the nested web root, we need to add the web_docroot line.
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