How does the heater work? Greetings to the forum

Hello together; would like to greet you as a new CR-V forum member; I am now proud owner of a Cr-V , year 2066, Diesel and of course have many questions: Are there any repair instructions from Etzold or others for this vehicle or other usable literature. Is the vehicle diagnostic and – and this is very important at the current temperatures – how does the heater work or how can I check its function? many greetings and thanks for the answers, and yes, I have already used the search function!!!! globus