In Tableau, you can import multiple XLS or CSV files and combine them into a union so that data from all files appears together as a single dataset. Here’s a step-by-step guide to help you do it:

 Step 1: Connect to Your Files
1. Open Tableau and go to the Data pane.
2. Select Microsoft Excel (for XLS/XLSX files) or Text File (for CSV files).
3. Navigate to the folder containing your data files and select the first file.
4. Click Open to load the data into Tableau.