dude you will get it quick, building a system is not hard at all..might seem hard but its far from beeing hard.
when you got the parts you cant really do wrong, every part fits at 1 place and so on so it almost build it self
and i dunno where the fun is that some say, i didnt find any fun in something that is so damn easy
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if you actually could do it wrong it would have been fun but you simple cant, well not if you dont use brute force while fitting the parts :P
so my tip is..just find out what parts a system need and off you go, your first system is done
but i must say it was much funnier (not that it was fun but still) to build a system 15years ago (i built my first system 15 years ago) than it is today, 15years ago every damn motherboard had shitloads of jumpers that had to be adjusted and so on (so it was not so good to loose the mobo manual), today you just plug all the shit in which is good but not as fun