They created many myths about these gods and their origins, as well as myths of great heroes and the interesting and the eccentric journeys they undertook. Note that these myths were the Norse people's religion. They were their explanation for creation, just as many in our society believe in Christianity today. .
Because the tales come from many sources over the past centuries, a considerable variety of details has developed in the stories told and the beliefs described in them. While there is indeed a pattern to speak of a standard Norse form of beliefs, the written record we have contains portions and discontinuous elements of myths that similar to Icelandic mythology. .
As in, there are other forms of mythology similar to Icelandic mythology out there. An example is our most prominent modern day religion known as Christianity. The similarities these "myths" share are phenomenal. They both have a creation story. In both there is a flood that wreaks destruction, and as well, they both have a character and a symbol that represents a new hope for them. For Norse mythology, that would be Thor, and his hammer. As for Christianity, that would be Jesus and his cross. No other mythologies, however, measure up to Norse mythology's complexity, style, and unique vibe. .
The cosmos of Norse mythology is divided into three levels, corresponding loosely to the realm of the gods, the realm of humans, and an underworld. These realms are subdivided into nine worlds, peopled variously by gods, slain warriors, elves, humans, dwarves, giants, and the dead. In the creation myth, the giants preceded the gods, who emerged from them to create the rest of the world. The giants and the gods were enemies, and much of the drama of the myths centers around their conflicts and, more generally, conflicts resulting from contact between their disparate worlds. After the initial emergence of the gods and the creation of the tripartite cosmos, there was a short golden age which was quickly disrupted by conflict and battles, especially between the gods and the giants.