When I hit one of the time options does the switch turn on? Or do I select the time interval and then hit the on switch?

Yes once the timer is wired properly you can push the button that you want the timer frame for. OPERATION This preset timer has two program sections: Option 1- indicator light OFF (default) Turn ON the connected light or fan by pressing the desired time button, or the ON/OFF button. If you press the desired time button, its indicator light flashes twice to show the new countdown interval is set. If you press the ON/OFF button, its indicator light flashes twice to show that the last used time selection was activated. When the set time is out, the indicator light under the ON/OFF will also flash twice. Option 2- indicator light ON Step 1: To change program from the factory preset mode (Option 1) so that the indicator light for the selected preset time button stays on for the duration of the time period, simply press and hold the top 2 buttons (5 min and 10 min) simultaneously. All indicator lights will flash once indicating program has been switched. Step 2: In this mode, when a preset time button or the ON/OFF button is pressed, the selected preset time button will remain illuminated for the duration. Step 3: To switch back to Option 1 mode, simply repeat above steps. Note: In the case of a power failure, the Preset Time Switch will switch back to the factory setting mode (Option 1). Manual OFF While a timer is active, you can press the ON/OFF button to turn OFF the connected light or fan immediately. Hold Mode(Continuous Operation) To turn timer On for extended periods of time, press and hold the push button for more than 8 seconds. Timer enters HOLD mode, the connected load is turned ON. To exit HOLD mode, press any button of the timer to turn OFF the connected load