How to create new canvas at photoshop and apply a layer by layer name?

Question

How to create new canvas at Photoshop and apply a layer by layer name ?
So simply what i want is
Create a new canvas certain size such as 150x40 pixels
Apply a layer to that canvas. Script will select the layer by layer name
How can i do that these 2 simple things with Photoshop scripting
CS6

Answer 1

JJMack wrote:
Something like var doc = app.documents.add(width, height, res);
When you write Apply a layer what do you mean Script will select layer by name. A new document will have a background layer or a normal layer do you want to rename that there is onle one layer. Or do you want to add a layer by name what kind?
thanks for answer. you know like background layer. for example when you are generating web buttons you are preparing background layers. it will select a layer like that.
also can you post full script here if possible ? thank you.
example : http://img12.imageshack.us/img12/844/examplepx.png
after this i will write a text on that canvas but i will ask that after learnt this 2 steps