If you need to clone a project within the Pantheon ecosystem Terminus is a great tool to use.
First, install Terminus and then add the site clone plugin.
After authenticating with terminus use the site:clone command
terminus site:clone <source>.<env> <destination>.<env>
<source>
and <destination>
are either the site names or the site UUIDs. <env>
is the environment, e.g. dev, test, prod or multi dev.