To operate your heater:
1. Make sure the left vent is closed (knob pushed in).
2. Open the right vent (knob pulled out)
3. There might be a pet****** on the back of the head where the heater hose attaches. It's not stock but common. Open it if it's present.
If you want floor heat, leave the defrost cable pushed in. For defrost, pull the cable out.
For hotter heat, pull the temp cable out.
Kaisers have good heaters but they are not strong units, like those on concurrent Nash cars, for example.
Your car should have defrost vents if there's a factory heater present.