In order to create a series of child nodes in a script transaction you must first create a new top-level node. By passing a set of arrays into the arguments of the technique a series of child nodes are created.

transaction 1 modelChange 'Add baseCS, Change baseCS'
{
    node User.Objects.baseCS Bentley.GC.NodeTypes.CoordinateSystem
    {
        Technique                 = 'AtModelOrigin';
        GraphLocation             = <auto> {40.0, 40.0};
    }
    node User.Objects.baseCS Bentley.GC.NodeTypes.CoordinateSystem
    {
        Technique                 = 'AtModelOrigin';
        DGNModelName              = '3D Metric Design';
        GraphLocation             = {29.167, 81.667, 174.0, 0.0};
    }
}

transaction 2 script 'pointArray'
{
    		Point pt = new Point("pointArray");
    		pt.ByCartesianCoordinates(baseCS, {1.2, 2.0}, {3.4, 4.5}, {0.0, 0.0});
}