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. Here are some commonly used open minor chord shapes.
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.
In this progression use a pivot finger when changing from C to A7 and Dm to G7. Use a slide finger between A7 and Dm.
Am
To play the Am chord, use the first, second and third fingers of your left hand as shown in the diagram. Strum all six strings.
This is the three four time signature. It indicates that there are three beats in each bar. Three four time is also known as waltz time. There are three quarter notes in one bar of ^ time.
The following chord progression is written in ^ time. To help keep time, accent (play louder) the first strum in each bar. Use your first and second fingers as pivots when changing between C and Am. Use your first finger as a pivot when changing between Dm and G7.