I previously wrote about model units and how this setting impacts the model appearance in a post called "Know your BIM 360 Glue units"
What if your models have the right size, but are all over the place and do neatly align to become your multi-disciplinary model? Transform is your tool for this. If you have used Navisworks before you have probably used the "Units and Transform" setting.
To access this setting open your merged model, then access the Models module on the left. From there you can select individual models and choose the Transform option.
In this dialog simply change the location through offsetting from the origin, rotating around the origin or applying a scale.
After you hit Save the settings are applied to the model and you will see it in the new position. This will also create a new version of the merged model. This lets you experiment with different values and go back to previous settings.
In an ideal world you would not have to worry about this at all. There is a BIM execution plan in place that defines a common coordinate system and origin. And when everybody working on the project adheres to these pre-agreed definitions using shared coordinates the multi-disciplinary merged model just falls into place.
Until then apply the Transform to move it to the right location. The good news is you really only have to do this once when you first merge the models. From then onwards it will just magically align.