Origami Studio use pt/dp coordinates instead of pixels. Specify position or size in pt/dp, and Origami will handle rendering layers at the appropriate density. For instance an iPhone 7 is 375x667 in points, but 750x1334 in pixels.
By default, the origin (x: 0, y: 0) is in the center of the device screen. On the X axis, coordinates increase as you move right, and decrease as you move left. On the Y axis, coordinates increase as you move down, and decrease as you move up.
For illustration, below is a Layer Group of height 400 pixels and width 300 pixels:
Anchor points change the origin of the coordinate system for that patch. Anchor points can be defined in the Patch Editor with a Point patch, where X and Y are any decimal 0-1.
Here's an example of a Text Layer positioned from the "Top Left" Anchor Point:
From the bottom right:
If you want to inset it by 40 pixels, give it an X Position of -40 and a Y Position of -40.
The pivot port changes the point about which a layer scales and rotates, and can be controlled separately from anchor points. Pivots can be defined in the Patch Editor with a Point patch, where X and Y are any decimal 0-1.