First, you'll need to know your organization's "Friendly URL" for SSO access to Anaplan. Then follow the steps to "Add your Friendly URL for SSO Access" at https://community.anaplan.com/anapedia/excel-add-in/installation-setup
When you're done setting things up, just click the regular Log In command on the ribbon to launch your organization's SSO sign-in page within Excel.
Hope that helps :D[url=https://community.anaplan.com/anapedia/excel-add-in/installation-setup]
Daniel, Anaplan staff