I'm trying to do something really basic. I want a view to fill half the height of the device and the entire width of the device. I want to use constraints to make this consistent across all screens. But I've had no luck. For the width, my idea was to set the leading and trailing edge constraint to 0. I'm not really sure the difference between Leading/Trailing and Left/Right constraints but I can't find Left/Right constraints even though I've seen people talk about them... Anyways I don't know how to manually add constraints. Well actually I know how to add Width, Height, and Aspect Ratio constraints by clicking the view and making go into "constraint" mode. I know how to add recommended constraints and edit them but it never gives me both Leading and Trailing. It's always one or the other. Can anybody help please? Thanks in advance.