Use the 'Get Data' feature in Power BI Desktop to connect to the SQL Server and Excel files, and import the required data tables without any further steps.

Create a new folder on your machine, copy the Excel files, and import them into Power BI Desktop as data sources, then manually adjust the data in Power BI.

Use Power Query in Power BI Desktop to transform and clean the data from both SQL Server and Excel files, ensuring consistency and accuracy, but do not establish any relationships between the data tables.

Use the 'Get Data' feature to connect to the data sources, transform and clean the data using Power Query, and combine the data using the 'Merge Queries' feature, then create relationships between the data tables.

All of the above