How do you read guitar sheet music?

I'm familliar with the notes and how to read them in general but I'm confused as to how it works for guitar. How do I know if it a single note or if it is a chord or is that the same thing?How do you read guitar sheet music?
if it is a chord it will have more than one note stacked above each other at once, try to find a song that has both sheet music and tablature right under it so you can easily compare them and tell how to play it