There are a few steps when viruses multiply. The first thing that happens is a virus will attach to a bacterium. Then the virus will be injected to its genetic material. Afterwards, the genetic material of the virus will be combined with the bacterium's genetic material. Next, the virus' genetic material will be detached from the bacterium's genetic material and the bacterium will bring out the virus' proteins and genetic material. Later on, new viruses accumulate. And the bacterium spurts open, releasing new viruses. However, there are also additional steps when viruses multiply. The virus' genetic material will turn out to be a part of the genetic material of the bacterium and then after some time the virus' genetic material will remove itself and becomes active.