It is always the easy stuff that is difficult. I have a stack of manuals, but no explicit directions for mounting the motherboard to the Case. The board has seated to the case with those mounting screws. (One short). Only two copper screws to secure the board to the case. DoesnÂ’t seem solid and can lift. What are those plastic thumbscrews for? Needless to say, i am a newbee and tolerance with my lack of confidence is greatly appreciated..