Within the Add Short-Term Forecast user interface there are four Creation Method options.  To import historical data to use within a Weighted Historical Index forecast, utilize the third option on the list “Weighted Historical Index with Source Data Import”.  This option was renamed and used to be called “Import Data” but it still functions the same way as in the previous version of workforce management.  This option allows the user to import up to 8 weeks of historical source data to be used to create a weighted historical index forecast one week in length.