I have natural light brown base color with golden blonde-colored full head foil highlights. I can't find anything online about the specific touch-up process. Just that it's the most complicated of all highlighting processes to maintain. I don't understand what they do, and I didn't bargian for a high maintenance hair color. Can someone tell me how foil maintenance works?

(The background to all this is that I walked into a retarted salon and said, "I'd like subtle full head highlights -" and before I could finish the girl pranced off into the back room and came out with the color already mixed and a box of foils. She didn't even explain what she was doing or give me options as to what kind of highlights I wanted. Luckily I love what she did, but I'm just apprehensice as to what I got myself into.)
Oh believe me, I'm not even considering doing anything myself. And the cost isn't my problem, it's the damage.