The mental model attempts to define a map of the user cognitive processes. Depending on how it's done it can help define what is the user looking for, what kind of decisions is she taking etc.

In my experience mental models serve more as a framework to refer to as once explores different possibilities. The mental model itself does not deliver specific design choices.

For navigation you still need to do exercises like card sorting, or do task flow diagrams etc. Once you have done those, the understanding of the mental model would help you evaluate the results and make better decisions.

The mental model attempts to define a map of the user cognitive processes. Depending on how it's done it can help define what is the user looking for, what kind of decisions is she taking etc.

In my experience mental models serve more as a framework to refer to as one explores different possibilities. The mental model itself does not deliver specific design choices.

For navigation you still need to do exercises like card sorting, or do task flow diagrams etc. Once you have done those, the understanding of the mental model would help you evaluate the results and make better decisions.