Typically, the tense marker ka is used to indicate that something will happen in the future. However, when telling a story, ka is often used to indicate that something happened next. Usually this will be in a situation where we have already established that the events are in the past. In the following example, the word inanahi sets the event in the past, and therefore ka is translated as a past event:
Inanahi, ka haere au ki Te Tai Rāwhiti.
Yesterday, I went to town.