You can use two differnt methods to order your layers. 


#1 - From the layers sidebar. 


Click the layers sidebar, you can drag each layer up and down to position the layer. 


Check/uncheck the eye button to hide the layer from view.

Check/uncheck the lock button to lock or unlock the layer (when activated the layer box will have a red border to symbolize it is locked)

Use the X button to delete the layer. 



#2 - Using the layer stack controls: