The custom tool bar shown at the top of the picture was created by touching the tool panel icons and dragging tools into it that I use most often in this case Fill, Line, Circle, Rect selection, Lasso selection, Wand selection, Clear layer, Export, and Save.
The visibility of the small reference image at the top left can be toggled by selecting the push pin icon at the top right. Or it can be removed.
The visibility of the Layers panel can be toggled by touching the layers icon at the top right. In this case I am using three layers. The bottom layer is the original painting and the layer above it is a duplicate the bottom layer that I have reworked. I can toggle the visibility by touching the eye icon in the top right corner of the layer so I can quickly compare the two versions. The top layer is typically where I add a signature. Some artists use lots of layers but I tend to use not more than five. Often times once I have painting on a layer the way I want it I will merge it with the layer underneath. There are a lot more things one can do with layers that I am discovering.
I usually keep the brush tool bar at the bottom of the screen. This is the tool bar that I use to choose brushes and control the brush size, color, and opacity. I can also choose the eraser which will let me use any of the brushes as erasers. This tool bar can be repositioned by long pressing it then dragging it to another location either docked or floating.
The custom tool bar shown at the top of the picture by dragging out tools from the tool bars next to it that I use most often. The small reference image at the top left can be toggled on or off by selecting the push pin icon at the top right. I can also toggle the visibility of the Layers panel on or off by touching the layers icon also at the top right.