Can really only answer no. 1.
Button down is LO. Button up is HI.
To downshift to low, push the button down just before you are ready to use it and use the clutch when shifting. When shifting this way you will get less "grinding" from the rear (when "split shifting" shift the trans first then hit the button down). Upshift anytime you are ready to use it and again use the clutch. Many don't use the clutch, but it is better to and it will shift smoother.
You may also want to do some research using the "Search" feature above. We have some very detailed info on file on shifting 2-Speeds.
Bill
