Hasta La Motion!

i am in the proses of trying to write a plug in
just for fun i guess

my question is i am trying to write a script that will
make a shape layer and then add parameters to it like fill stroke
and modifiers

since i have absoulty no idea what i am doing
i am using the adobe scripting guide as a basis for every thing
so by sayinng : app.project.item(1).layers.addShape()

that makes an empty shape layer

but i have no idea how to add parameters to it

the script guide says

var myShape = new Shape() ;
myShape.vertices = [[300,50],[200,150],[300,250],[400,150]];
myShape.inTangents = [[55.23,0],[0,-55.23],[-55.23,0],[0,55.23]];
myShape.outTangents = [[-55.23,0],[0,55.23],[55.23,0],[0,-55.23]];
myShape.closed = true;

to make a oval but that dose not seem to work

any help ?