Which device do you have? There is a wheel on the front of the IC that lights up blue on the large units, might be a different colour on the Nano. Spin this to set the temperature manually.
It is much easier to answer a simple question if it is asked clearly and with some background information to support it.
All devices ship with a quick start guide which explains its use. Further information is available in the support section of the website including FAQs and videos on set up, cleaning, etc.