1. Go to your home screen's list of app shortcuts. This is usually accessible by long pressing on an empty space on your home screen and choosing either "shortcuts" or "widgets", but may be slightly different for your home screen app.
2. Find the Squid shortcut titled "Open Notebook", then long press on it and drop it at the desired location on your home screen.
3. In the dialog that appears, choose the notebook you want to open to.