Unlike the national stock exchange, a forex market is multinational and a lot more volume is traded on it. Hence you, as an individual investor with foreign exchange, might not have much of a say in the price fluctuations and demand, as there are other institutional investors that are trading in a much greater volume.
In case you are completely unaware of the market trading, it is essential that you first enroll yourself in some financial literacy classes that will teach you the basic economics of demand and supply and how it affects pricing.