Use the buttons on the right hand side.
TRA trim all or Lshift + numpad 5
TRV trim vertical or Lshift + numpad 1
TRL trim Lateral or Lshift + numpad 2
TRF trim F/A or Lshift + numpad 3
Have been looking at Blender and Wings3d myself over the last few months, I found Wings3d easier to use initially but persevered with blender and once you get used to it's interface you realise how powerful a program it is.
Here are some of the resources I have been using...
If you have downloaded spacecraft 3 from vinka's site http://users.swing.be/vinka/
you will have a folder "add-on docs" in your orbiter install directory in there is spacecraft.pdf.
Tutorials :- Tutorial: How to use Spacecraft.dll (Lesson 1)
:- Tutorial: Spacecraft3.dll advanced...
The Catcher in the Rye by J.D. Salinger, I loved this book as a teenager , and I'm happy to say that at least 40% of these Titles I have in my personal library. Surprised that Heinlein's Stranger In A Strange Land Isn't Mentioned