I'm building a computer?

I ordered everything, and it's coming today. the case (raidmax quantum) and keyboard came today. I hope I do well, but my main question is that should I be really firm with my parts? :/ it sounds dumb, but I tried taking the side cover off my case and It wouldn't come off. All the screws were out. Should I just pull harder? And, is it safe to use a medal screwdriver to unscrew and screw the screws on and off, on all parts like the motherboard?