HOORAY
Glad to see that you have your new lens... I am certain that you will enjoy using it.
A trick which you probably know...
If you put this lens in the manual mode, there are two scales to work with: The first scale (at least on my copy) closest to the front of the lens is the magnification (1:1 to 1:10). It is easy to decide what image ratio you desire and then just move the camera/lens back and forth until the image is in focus. When it is in focus, you will be at that magnification. The second scale (which works in concert with the magnification scale) is the distance scale. You can easily get used to the lens to subject distance you need to be in order to get the magnification you desire...