He already watched her for sometime (thus knows her car). I doubt he followed her but just happen to see her car in Puchong (what luck!). He then took it as a sign it is some divine will that they are fated to be together and left a handwritten scribble for her. Only to be called a stalker and made famous on the internet. I kinda pity the guy but all pity is lost when he wrote "who is me"