I want to jump the cursor 5 lines down. Instead of hit "down arrow" key  5
times, is there any way I can use a keyboard shortcut to do it?

Another question is there a place I can assign keyboard shortcut. I know in
tools/options/environment/keyboard you can do it. But in my case, if I want
to assign a shortcut too move cursor down 5 lines and another shortcut to
move cursor down half a page with the cursor vertically locates in the
center of screen, how can I do it?

Thanks

-fj