To unlock the Guide trophy in Metro Exodus, you must make your way through the research facility found towards the end of level 10 without killing any of the "Blind One" enemies. There are five "Blind One" enemies in total, you will know which ones they are as they look like large gorillas.
The easiest way to do this is to play on the easiest difficulty and speedrun through the level. If you do get hit by one, just carry on moving without retaliating.