Tableau Data is interactive so click the icon above Approx. Number of Students on the left to sort low to high, high to low. Click on courses legend to highlight one and then choose "Keep only" to remove other courses. to get back to the original chart click the back arrow on the bottom right side. To focus on some schools use the "School Name" drop-down menu to select the schools that interest you. Finally, you can click on the questions on top to change to another Visualization.