The position of a primitive or entity is based on the 3D space with the coordinates x, y and z in the following manner. You can use your right hand to understand the coordinates:
The units are Meters. If you do not define a width, height or depth, A-Frame uses the standard size of 1. The position is always in the middle of the primitive or entity.
<!-- Box with Zero position --> <a-box id="box" position="0 0 0" color="#4CC3D9" ></a-box>