In order to add PDFs to your project, you need to transform them to a location in the model.
1. You hover a place in the model, where you want to move it to. Make a note of the x, y z
2. Hover the PDF(s) in the same location (a corner of a building or the like) that you want to have it moved, and make a note of the x, y and z.
3. Go to Projects, find your PDFs and select "Transform"
4. Add the change:
Transformation = New coordinates minus existing coordinates
Example:
x = 106661.239 - 203623 = -96961.761
y = 1213583.85 - 2345509.697 = -1131925.847
z = 50.383 - 47.704 = 2.679
Scale / Rotate accordingly