The data discussed shows that masks reduce the change of becoming infected with Covid19, though as with any such virus, it probably won’t prevent you from becoming infected if you are exposed to it. Only a vaccine would do that, Fortunately, for most people, becoming infected with Covid19 rarely makes you sick. If you feel that avoid Covid19 is a life or death matter (e.g. an 85 year old with a dysfunctional immune system and lung diseases), rather than relying a mask lowering the probability of becoming infected, you should isolate yourself in sealed environment which would probably prevent catching the virus.
An analogy would be walking out into a battlefield with or without a kevlar vest. The bulletproof vest will certainly reduce your chance of being killed, but it won’t prevent it (e.g. many soldiers in spite of wearing them). To avoid being shot, it is best to avoid going to a battlefield.