Go to Shape Fusion.
Click at 'List of Scans' on the '+' (Top right).
Upload your first fusion. Then in the same way the other ones. They will have different colors but they will lay precisely one above the other. So you must separate them on the screen for comparison:
Click with the left mouse button on the name of the first scan. It will be red highlighted and a hook will be set.
Hold the 'Ctrl' key down, go with the mouse pointer on the scan(s), press the left mouse button and shift the first scan from the other ones. Remove the hook in the list.
Do the same with second scan. And so on.
With the right mouse button you can rotate all scans (together). If you want to do it with only one of them so set a hook at its file name and press the 'Ctrl' key during rotation.
PS. With the '-' sign you can remove a scan from the list (and from the screen).
The PNG file shows the texture of the scan (if it was captured). You can switch it on and off by e.g. pressing the 't' key. Or more official, with the rainbow symbol below 'Visibility'.
Edit: You can upload the 3 scans in one go. Mark them before.