There are two ways the top level of a Kialo discussion can be structured - multi- or single-thesis.
A single thesis discussion has one thesis or central question, with two directly oppositional sides. For example:
A multi thesis discussion has two or more theses, each of which proposes an answer to a central question. For example:
The starting structure of a discussion is set up when you create it. For information on how to change the type of discussion, see Changing a Discussion Between Multi- and Single-Thesis Structures.