You don't want a thick layer of granola on your pan. It will not bake evenly. The thinner the layer however the more chance it will have to burn so keep a close eye. Every oven is different!
Turning the pans means exactly that. Turn the pans so that the granola bakes evenly. Ovens can have cool and hot spots. all my granolas taste better on the well done side but there's a fine line between well done and burnt. Please don't let it burn.