I have loaded several layers onto my map. How can I toggle between them to see just a few at one time?

Go to the legend on the right side of the page.

legend

You can uncheck layers you’d like to turn off. If you want to re-order data layers simply left-click on the item in the list of map layers and hold down as you drag the item to the preferred order location. If you want to label an item click the “Label” box to see data values or names on the map.