Scirocco Central

Hi, I have a 2010 vw scirocco and it has a heating issue I can’t figure out.
The system gives out really cold air but when I turn it to heat it’s just blowing out air in normal temperature.
What things and common things should I check? And how is the ac system built if anyone can explain.
Thank you.

Airflow direction, including the mix between hot and cold, is controlled by a group of electrically operated flaps. It's worth getting the fault codes read, which should pinpoint any electrical components that have failed, but it's also possible a mechanical linkage or gear has failed. I don't know the specifics for the Scirocco, but access to ventilation components can be awkward and time consuming