The Bohr model represents elements as atoms with different energy levels surrounding the nucleus.
For Hydrogen, it contains one electron. So its Bohr model would look something like an H in a circle with one dot on this circle. Sort of like, ( H *), where that ring represents the first energy level and the dot represents the one electron. This ring, represents the first orbital of hydrogen which can contain two electrons total.
Emission of light can be discussed using the Bohr model because it's easier to think of the energy levels. The electron which surrounds hydrogen is said to be in its excited state. This means that it contains energy. When this energy is released, it is in the form of light. So, the Bohr model shows what energy level an electron is in, where higher levels have a greater energy.
The Bohr Model was replaced by the electron cloud model. This is because it is a more accurate representation of how an electron surrounds the nucleus. It is not stationary, but rather constantly moving.