In the builder, you can utilize the ‘Owners’ tab to set who would be assigned this step.

owners-tab

Options and what they mean:

owners-tab

The user starting a run will be assigned to this step by default. Only this user will be able to mark this step as done.
Regardless of who starts the run, this step will be assigned to ALL users in the organization. Every userwill be able to mark the step as done.
You can pre-determine which users get assigned this step, it could be individual users or a group (Groups can be created via ‘Manage accounts’). This feature is perfect for approval steps.
4.      
This will add a ‘Re-assign’ button to the step, allowing anyone to re-assign this step to another user. Perfect to use if someone needs to handover or if they are unable to do the step:
reassign
5. Check this box if a guest (user outside your organization) can own this step
This allows the user starting the run to assign this step to a guest user (any email address).
If you need have any other questions, please contact us.