1) Select the model in the Available Models list, then select Execute Model -> Schedule It from the Selected Model menu.
2) The Scheduling dialog will appear. See https://support.lityxiq.com/882325-Using-the-Scheduling-Dialog to get help with this dialog.
In the case of scheduling models to run Upon Data Refresh, LityxIQ will continually look for a new version of the modeling dataset. Once that dataset has been updated or refreshed within LityxIQ, a new version of the model will automatically be executed.