Now to begin the denouement (What? The denouement is the final outcome of the story in literature). As said and worth repeating - do not use a demand curve or a supply curve on its own the whole point is to put them together into a single diagram to establish equilibrium so as to make predictions, outcomes etc.
Syllabus: Explain, using diagrams, how demand and supply interact to produce market equilibrium.
Analyse, using diagrams and with reference to excess demand or excess supply, how changes in the determinants of demand and/or supply result in a new market equilibrium.
Equilibrium (starting Point)
Shift of a curve (when a non-price determinant changes)
Excess (demand or supply)
Moves along both curves (NB new curve that has shifted)
Learn this and you will never go wrong on questions about the price mechanism and resource allocation and now for the detail...