How do I set a Nexus Automatic to clean at a set time each day?

As its an analogue timer the cleaning frequency will be purely based on time so for example once every 24h, you can dictate the time by pressing manual clean at say 6pm and then it will automatically clean at 6pm the following day. On a twice a day clean you would need to set it to twice a day and then select a manual clean at 9am it would then cycle 12 hours and do a clean at 9pm.