Note values determine the length of a beat.

In 4/4 the notes values are:
4 beats for whole note
2 beats for half notes
1 beat quarter note.

Whole notes have four beats so to count a whole note it would be 1,2,3,4.
Half notes have two beats so to count a whole note it would be 1,2.
Quarter notes have four beats so to count a whole note it would be 1. Eighth notes have ½ of a beat so to count a whole note it would be + or ‘and’.

One of Eighth notes would be counted as:

/     /     /     /     /     /     /     /
1   +    2    +    3   +     4    +

When two eighth note rests are used in a 1,2 count

/               /              /            /
Eighth     Eighth     Rest     Rest 

The two rests in between must be eighth note rests and not a quarter rest. This make reading the music much easier.

Dotted Note

When a note has a dot next to it, the value is increase by half the note value.

A dotted whole note would have 6 beats.
A dotted half note would have 3 beats.
A dotted quarter note would have one and half beats or ‘1 +’ beats (a quarter and an eighth note combined).

A rest can also be dotted.