
The Melodic Minor changes depnding if you play upwards or downwards. in the first example below we see the acending melodic minor scale. (playing upwards in pitch)

Below is the Decending Melodic Minor Scale. (played downwards in pitch)

As always, you can position this anywhere along the fretboard to change the key.
Practice this scale moving up and then practice the scale backwards (down), start off slowly and eventually build your speed up as you gain confidence. Remember to pay particular attention to the changes from acending to decending.