Certain Settings on your viewer make your combat more intuitive, and easier to navigate. Instructions : in Viewer top go to :Avatar>Preferences>Move and View. Basically you want to enable everything in the Mouselook Functionality Section. Also, you may want to consider adding Sun Moon Shadows in the Graphics Tab. Your Mouselook section should look a bit like this when done:
You may want to play with the settings a bit and use the slider for the sensitivity section. its all good and all to make your combat more enjoyable.