Here's how to estimate user stories using relative sizing with a one point story as the reference point:
1. Choose a reference story: The team selects a reference story that is considered to be a small-sized story and assigns it a value of 1 point.
2. Estimate the other stories: The team estimates the size of the other user stories relative to the reference story. For example, if a story is considered to be twice as big as the reference story, it would be assigned a value of 2 points.
3. Use whole numbers: The team can use whole numbers to assign values to user stories, as they are easier to work with when using a small reference point.
4. Discuss and refine estimates: Once the initial estimates have been assigned, the team discusses and refines them based on their understanding of the story and any additional information that may have come to light.
5. Review and adjust estimates: The team regularly reviews and adjusts the estimates as they gain more information about the stories and as they complete work on them.
Using a one point story as the reference point can be useful for teams that work with smaller, less complex stories. It allows the team to estimate the effort required for each story relative to a small, easily understood unit of work. As with any estimation technique, it's important to regularly review and adjust the estimates based on new information and changes in the team's understanding of the work.