I can not fully understand with a sentence, i need your help

I was puzzled with a sentence when i read a passage called LES , would you like to give me a hand ^_^ . It is said a boy fall in love with a girl ,but the boy is so curious why the girl refused him when he asked her to allow him to walk her home, so one evening ,the boy dicide to follow her.However i can qiute see the meaning of "I carefully hide behind trees and bushes as i followes her down the trail beside the river", i can not fully make it clear,the "follow……down "is a phrase or follow here is matched with "the trail"?can you explain the construction and traslate the sentence into chinese for me ：） i am very appreciate for your help^_^