How to read a chord diagram
The diagram shows the neck facing you, headstock at the top: vertical lines are strings (lowest on the left), horizontal lines are frets. Numbers in the dots are fingers: 1 index, 2 middle, 3 ring, 4 pinky.
An o above a string means it is played open, an × means it should not ring. A bar across several strings is a barre: one finger presses all those strings.