Using layers

Am using Sketchup 2017. And i want to use layers.When look about this on youtube i see layers directly on the working area.
When i klick on toolbars for layers it not showing it on the working area,but only on the top.
What do i wrong?

Look in Window>Default Tray. Make sure Layers is selected to be included. And make sure the Default Tray is set to be visible.

Before you get into using layers make sure you understand their proper usage including leaving Layer 0 active at all times and leaving all geometry with the Layer 0 tag.

Thanks. I gone try it.