How to attach lines to GLTF model

Hello. I have loaded a 3D GLTF model and it currently appears on top of an AR marker (using AR.js).
I need to add text and lines that point from text to certain aspects of the 3D model. I would also like to rotate the model in such a way that either the model stays still and the user can move their camera around it (with the text rotating on its y-axis so that it is always facing the user) or the model rotates based on the camera angle and maybe the text appears when the certain aspects of the model are visible.
Another option I’ve considered is attaching points to the 3D model in which the user can tap to show the text.
I am currently using AR.js and a-frames (high-level three.js), so I’m not even sure how to render an animation loop with these in JavaScript (I assume it’s the same, but I’ve tried to no avail).
I’m not asking for code, rather just a direction to go. Sorry for the vague question, but I truly am stuck!