Hello,
Have a look at this
post. It shows you how to assign the next task to a specific user.
If you want to assign the task to a role and not only a user, you need to create a list having as type: Entities or Roles instead of USERS.
Then, you have to create a Role from the organization tab. You tick Dynamic Role.
And within your process, you assign the task to the Dynamic Role.
You add to the property role id within the config of your dynamic role task, the value of the selected Entities or Roles list from your web interface.
Regards,