Replying to The most asked questions asked again... Detuning

Okay ive seen millions of threads on NS here and there is such a divided opinion on it, i cant decide what to do. This will be my first year skiing park mainly so i have 0 experience with ski detuning and such. IF i want to detune the underfoot of my skis, should i just bring it to a shop? will they know what i want? or should i do it myself and buy a file and gummistone online? And if i buy the file, does anyone have a site that can show me how to do it? so in the future i can be better off in this situation.

Thanks guys.