Although I am not yet familiar with the Viewer3D.js (version 7), we are exploring the possibility of using the APS Viewer API to meet customer needs.
We need to display multiple 2D drawings together in one viewer, and I know we can use Aggregated View API to achieve this.
When I load two 2D drawings in, they will be displayed in the middle of the viewport and fill the viewport.
But this brings about the following three issues.

we have used forge Viewer to display the BIM models. But if we click any equipment listed in the Tree Selecion, In the Forge Viewer equipment not Zooming.
Kindly help us to get the selected equipment Zooming in the Forge Viewer. Kindly share the sample code for our reference.

Is it possible to add an object to forge viewer. I know that it is possible to add custom geometry using three.js, but I want to add an object that will be part of the model I’m uploading. Have the same properties and so on

I want to add annotations to parts of my model, but I don’t understand how to do it. To make you understand my idea, I will attach a photo as I see it. So that when I click on an object, menus appear that I can edit
Could you help me, where could I read about the implementation of this?

I use the Draw Tool Extension to create objects in my scene. But they are created simply as three objects.js. I want them to be clickable and be part of the Autodesk Forge Viewer model. I’m new to Forge, and I don’t understand how to do it or where to read about it at all.