There are two ways the heart can be dissected to reveal the inner chambers.
Technique 1: A coronal cut involves carefully cutting the front of the heart from the back of the heart. This exposes all four chambers of the heart: right and left atrium, right and left ventricle. With this technique, you can view the septum, which divides the left and right side of the heart. This cut can be difficult to make because you must cut the heart in half evenly.
Technique 2: Make a straight cut through the left atrium and left ventricle. Repeat on the right side. These cuts are easier to make but you must view each side of the heart through each single cut.
In both cases, cuts are made in such a way to reveal the two atria, the two ventricles and the valves that connect them.