Starting a new home aquarium is not the simplest thing to do. There is a lot more to it than going out and buying an aquarium, various decorations, a heater, a filter and some fish. It takes some studying and planning ahead. You should think about the types of fish you wish to keep and what size of a tank they will need. A little research and some careful planning can eliminate a lot of heartache and stress down the road.
Getting it all set up and going isn't something that can be done in one day. It takes several weeks to get the water cultured properly and a healthy biological filter established. During the first few weeks new aquarists get frustrated when they buy the fish they want only to have them die a week later. Doing some research on something called "new tank syndrome" and selecting a few hardy fish to start with can help to avoid all this.