A typical bar chart will have one or more dimensions on the Rows and a Measure on the Columns for horizonal bar chart, or vice-versa for a vertical bar chart.
Double-click Sales. This will put Sales on the Rows (alternatively drag Sales to Rows or to the y-axis).
Double-click Category. This will put Category on Columns (alternatively drag Category to Columns or the x-axis).
Double-click Sub-Category. This will put Sub-Category on Columns (alternatively drag Sub-Category to Columns or the x-axis).
Notice the Marks Card is set to Automatic in the dropdown box. Tableau will automatically create a bar chart based on this data. You can select Bar in the dropdown menu, but in this case it doesn't matter. You should now have a vertical bar chart similar to the image below.
Click the button to swap Rows and Columns. This will rotate the chart, moving all of the pills on Rows to Columns and all the pills from Columns to Rows.
