The following example uses what is commonly known as a riff. A riff is a short musical idea (usually one or two bars long) which can be altered and varied to fit a chord progression. This one is an example of a riff applied to the 12 bar Blues progression.
A dot written after a quarter note means that you hold the note for one and a half beats. A dotted quarter note is often followed by an eighth note.
This melody makes use of dotted quarter notes and also contains the new C note you have just learned.