As a prerequisite, you'll need to enable the time dimensions. The steps to do so are here
Navigate to the Content Network area of SAP Datasphere and click on Business Content.
The available business content is displayed. Select the item SAP Ariba: Spend Analysis. The Overview screen for this package is opened.
If you download or deploy the Spend Analysis package for the first time, you don't need to change any of the default settings under ‘Import Options’. You will deploy all views manually. Because of this, check that ‘Deploy after Import’ is not selected, and click Import
SAP Datasphere downloads the content in the background. When the download is finished, you can check the import summary screen to confirm the content was downloaded.