How to pin a Group at top left of viewport?

I’m using the Genogram sample. After I created a group, I want to pin it at top left of viewport. this’s my code.

const newGroup = { key: 'e47b1dc9-ecd2-4a93-88c5-73872c0f2954', template: 'maingroup', isGroup: true, text: '', location: new Point(0,0) } this.diagram.model.addNodeData(newGroup);

That didn’t work.
Please give me some instructions. Thank you.

Please read:

Thank you!