Replying to Ski tuning help

Ok I ride park basically 99 percent of the time and have new line blends but am unsure about how 2 tune them. I always see pro skiers like rubbing there edge of one ski on the base of the other ski and am unsure what that does so someone please help me with that but I've always just had my friends defund my edges but he's not where I live anymore so I am unsure how to go about that as well. So basically what should I do to my base and what should I do to my edges. The skis are brand new btw. Thanks yal