To upload a .xls file and create a dataset and report using Power BI Embedded, you would typically use the Power BI REST API. Here is the basic process:
Upload the .xls file to a cloud storage service such as OneDrive, SharePoint, or Azure Blob Storage.
Use the Power BI REST API to create a dataset from the uploaded file. You'll need to specify the data source type (e.g. "excel"), the file location, and the credentials for accessing the file.
Once the dataset is created, use the Power BI REST API to create a report based on the dataset. You'll need to specify the dataset ID and any desired report properties such as the theme, visualizations, and layout.
I hope this helps!