The Dynamics 365 recipe requires Workato connections for both Dynamics 365 and SharePoint. These connections are under the same Office 365 account but use different Azure AD registrations.
Refer to the following document to properly configure your connections:
Dynamics 365: https://docs.workato.com/connectors/dynamics-crm.html (use a cloud connection)
SharePoint: https://docs.workato.com/connectors/sharepoint.html
You can leave the SharePoint site field empty. The recipe will automatically detect the site.