Archaeologists and historicans do not know very much about how the Vikings worshipped their gods. There are tales of "magic trees". Perhaps the Vikings built wooden shrines or temples. Once the Vikings began to migrate to other areas like Britain, France, and Germany, they were introduced to Christianity. Some Vikings became Christians. They built churches and hung crosses. Some Vikings continued to worship the old gods. Some did both.
Old warriors especially believed in the old ways. There was a place in Norse myth called Valhalla, where dead heroes were honored with banquets and feasts. Valhalla was in the palace of the greatest god of all, the mighty Odin. The sure way a warrior could reach Valharra was to die in battle. After a Viking warrior died, he was buried or cremated with some of his belongings. The dead body of a Viking chief might be put aboard his beloved boat. The boat was burned or buried so that the chief would have his boat with him when he entered Valharra.
In the Viking world, there was no group whose job it was to be a religious leader. There were no set rituals. The Norse all knew the Viking gods and loved to tell stories about them. Even though Odin was king of the gods, Odin was worshipped mostly by kings and warriors. Mothers often gave their new born babies a charm of Thor to wear to help keep them safe. But religious rituals practiced by the Vikings, if any, were up to individuals.
Even when Christianity entered the Viking world, Norse law ruled daily life, not religion.