In general, the two front buttons of your Slate have the following functions which are notably very helpful in screenless mode:
Managing pages (left top dot button)
When you start writing on a new sheet of paper or a new notebook page in Screenless mode, you must tell the Slate to create a new page.
To do so, click the New Page button (Top dot button): the front LED blinks white when a new page is created.
Managing layers (right top dot button)
Click the New Layer button (Top button) to create a new layer in Screenless mode.
You can create up to 5 layers per drawing in Imagink on iOS, and up to 10 in Imagink on desktop.