This is a sixteenth note.
It lasts for one quarter of a beat.
There are four sixteenth notes in one beat.
There are 16 sixteenth notes in one bar of * time.
Notice that there is a different sound used for each part of the beat when counting sixteenth notes - one ee and ah , etc.
Once you are comfortable playing sixteenth notes on a single pitch, try using them to play the D major scale, as shown in the following example.
Here are some examples which feature the use of sixteenth notes. Take them slowly at first and count as you play. Tap your foot on each beat and remember that there are four sixteenth notes per beat. Because the notes are closer together here, you will need to breathe after a quarter note, or even an eighth note sometimes.
Neither of these examples contain any articulation markings (e.g., staccato or slurs, but feel free to experiment with both). Generally the use of slurs is more common where the rhythms are faster as this produces a smoother sound.
Once you start improvising (e.g., taking a solo in a jam session) the expressions and articulations are left totally up to the performer. Get in the habit of experimenting with different ways of playing each new melody you learn.