Mortgage payments are typically made up of 2 parts: the principal and the interest. The principal is the money you borrowed to purchase your home, while the interest is the loan carrying costs charged by the lender for lending you the money.
Your monthly mortgage payment is simply the sum of these 2 amounts divided by the number of months in your loan term, such as 5 years, whereas your interest is amortized over the life of your mortgage.
The mortgage payment is used to pay the interest first and then the principal. As the mortgage life progresses, the amount going to the principal keeps increasing, and the interest portion keeps reducing until all the principal is paid off. The portion of your ownership of your home, which is made up of the principal that is paid off and an increase in the value of your home, is called your equity in the property.