First differentiate between the respiratory and metabolic.
The respiratory one has to do with breathing in and out (that is ventialtion) while the metabolic has to do with processes inside the body.
Know what each one is:Respiratory
Respiratory acidosis happens when a person is hypoventilating. In this case their respiration is depressed and so they are retaining carbon dioxide leading to acidosis. This could be caused by depression of the respiratory center.
Respiratory alkalosis is caused by hyperventilation and in this case,carbon dioxide is being exhaled in larger quantities than normal so the person is losing a lot of it leading to alkalosis.It could be caused by anxiety.
Know what each one is:Metabolic
Metabolic acidosis occurs when there is loss of bicarbonate from the body. This can be caused by diarrhea.
Metabolic alkalosis is caused by the loss of acid from the body, and increasing bicarbonate in the body. This can be caused by vomitting.