lol annoying noobs,

ok so can anyone make a tutorial on using playerpos and playerrot on gamerules? i know what they are, but i cant use them effectivly. and explain DQ flags/server flags, and how they affect gameplay (i know what the flags mean, instagib, none DQ, no damage, blah blah blah, but like why do you need it? i find no diference if i change it)