The first step is to find the icon of SketchBookApp in your mobile phone or iPad.

Step 2, after entering your canvas, select the icon indicated by the arrow above, which is a square.

Step 3: Click and a box will appear in the middle of the canvas. Click on the gallery.

Step four, you can see all your sketches.

Step 5, click the icon in the lower right corner, and you will see a box with deletion in it.