By default we have the o4-mini model by OpenAI selected. We have a few more models that you may prefer to use. If you want to switch the model you are using you click the drop down arrow in the interface

Model Selector with Green Arrow pointed at upside down carrot dropdown button

This reveals a menu with several models and agents to select from. To switch you just click on the model or agent you want to use and the interface will switch to that model.

List of Models on CatChat

When you select that model when you chat in the interface you will be chatting with the new model.