How do you add freon to a 98 Buick Riviera? It is blowing out hot air. on 1998 Buick Riviera

The 98 Buick riviera is blowing out hot air. Someone said it might need freon.

Asked by for the 1998 Buick Riviera
Youtube have some good instructional video clips.
Autozone have some popular workshop manuals for free on line once you register (for free) on their website There is a company that independent auto repair shops get their information from, this same information is available inexpensively for people that work on their own cars.. The information is year make and model specific, covering repair procedures, torque specifications, fluid capacities and specifications, service bulletins, component locations, wiring diagrams ect.... Alldata is very easy to navigate