Question Placing Revit model into AR Tracked Image Manager

I have a basic revit model (the walls and doors of my room). I've exported the .fbx into unity and created a gameobject, which has been added to the AR Tracked Image Managers Tracked Image Prefab. So once I scan the reference image it populated my prefab.

My confusion is in how to align the direction of my prefab so that it aligns with the actual walls of my room.

Looking for some pointers on this as my goal is to overlay construction plans over the bare walls to show exact placement of cutouts and objects etc.

I've also noticed that my AR image seems to float around and isn't exactly stable.