Located at the bottom and opened by default, is the Assistant bar. Here you can find the modifier keys Shift(1), Ctrl(2) and Alt(3), Copy(4), Paste options(5), Delete(6), Select/Deselect All(7), Arrange options (8), Fullscreen shortcut(9), Group(10), Ungroup(11), Convert to Path(12) and Help options (13).
To hide/open the assistance bar, click the arrow on the top-left of the bar:
How to use the modifier keys
To use the modifier keys (Shift, Ctrl and Alt) located in the Assistant bar, for example, to lock a moving layer in a straight line or duplicate an element, press the modifier key with one finger and move the element with another.