Editing properties
The Property Inspector is a panel on the right side of the application that allows you to set some common properties such as alignment, position and size as well as settings specific to certain UI elements (selection state, text properties, color, etc.). It is available when selecting UI elements, assets, and Components.

You can hide the Property Inspector by pressing the keyboard shortcut CTRL/⌘+; or ALT/OPTION +ENTER. When hidden you can also show it by right-clicking a UI element and selecting "Properties...".
If you have multiple UI elements selected it will show properties that are common to all selected UI elements as well as options for aligning and distributing.