Please refer to the following explanations in order to change the layers order.
▼ Web Browser
You can change the layers order by clicking on the layers on the right edge of the drawing screen and pulling them up or down.
▼ iOS
Please tap on the layer mark on the upper right part of the drawing screen.
Tap on "Sort", and a three-lines mark should appear on the right side of each layer.
Move the marks up or down to change the layers order.
▼ Android
Please tap on the layer mark on the upper right part of the drawing screen.
Tap and hold the layers you want to move and drag them up or down to change their order.