No need to be confused. The month when Passover occurs is also a Rosh Hashana but in a different way than “the” Rosh Hashana we usually think of as the Jewish New Year.
The month when Passover occurs (Nissan in Hebrew) is considered the first month when counting the months of the year. This is based on the verse (Ex. 12:2) "This month (of Passover; Nissan) shall be for you the first of the months of the months of the year.”
The reason for this is because it is the month of the Exodus. In this month God took us out of Egypt and we became a new “nation”. Therefore it is the first month of the Jewish People as a nation. When we call the month of Passover the first month of the year it serves as a constant reminder of the great miracles which accompanied our liberation from Egyptian bondage.
The “traditional” Rosh Hashana, which is six months later, is a New Year in a different and more universal sense. Rosh Hashana commemorates the creation of Mankind. Its Hebrew month is called Tishrei and it is the seventh month of the months of the year. Since it was when the world and Mankind were created the years are counted from this date. For example, when next Rosh Hashana comes it will be the year 5776 from the time of Creation.
Hopefully this makes things clear and “simple”. Rosh Hashana in the fall is the date of Creation of the world and Mankind. Therefore it is also the “Day of Judgment” for all Mankind. Passover’s month, however, is the first month for the Jewish People since that is when we became a free nation — a nation which has a unique identity and purpose in the world to pursue the way of ethical Monotheism that is taught in the Torah.