Those three elements, that in certain ways are connected one to another, may have shaped drastically life of humans precursors. Bipedalism of course, is the most important factor represented in this image, because it gives a reason of how this may have been an advantage for early hominids that allowed them to free their hands, carry food and children, and subsequently after necessity arose, usage of tools. Some other hypothesis on how bipedalism started can be connected to climate change and environmental adaptation. Our ancestors are always depicted leaving an area not suitable anymore for living, and that is where the first footprints of bipedalism were discovered. Two adults and a child, probably a family, leaving the area known as Laetoli, in Tanzania, leaving behind them an unforgettable sign of their existence. Their footprints still remain today. They were discovered by Mary Leakey, in 1978.
Tools usage must have been essential in different ways, as for example self defense from predators (trowing stones to predators), or simply for acquiring food (picture on the right, by pfctiranny.com). Carrying food is a result also of bipedalism, which helped early hominids to provide themselves with more food sources.
courses or ceremonial rituals of first hominids. Some researchers advanced this hypothesis, even though it seem clear that in order to cross a river, apes today tend to do it only with their feet. Even ceremonials and rituals are unknown at this point of time. Some early humans are represented in pictures burning mate corpses, after their death. It makes sense if we consider that humans may have started ceremonial rituals after realizing that dead bodies were only considerable food sources for vultures and hyenas (left picture taken from history.com)
We cannot really tell what happened during this period of time, but by showing some hypothetical and unrealistic (we cannot really know) events, we make ourselves different questions that lead us to different interpretations.