There are three main types of chords: Major, Seventh and Minor. The chord symbol for the minor chord is a small "m" placed after the letter name.
Dm
To play the Dm chord, use the first, second and third fingers of your left hand as shown in the diagram. Strum only five strings.
Rhythm Pattern
The accompaniment to the following example contains a D minor chord, and the melody uses notes on the 4th string.
The use of pivot fingers will make chord changes easier.