if you have some theory, then the string setup on a guitar is like so

E
A
D
G
B
E

every number represents the fret position of the note.
notice that some tabs are written upside down, so the high E is at the top.
counting up by half tones you can easily get to the right notes.


Am:
---x---
---0---
---2---
---2---
---1---
---0---
(A,E,A,C,E)