We have a Carrier 58PAV and the Red LED light is on. Furnace makes a high pitch noise when starting up.

We are having trouble understanding the directions provided in the manual to do the component test.

Instruction manual says to "To initiate the component test sequence shut OFF the room thermostat or disconnect the R thermostat lead. Briefly short the TEST terminal to the "Com 24V" terminal.
What is the R thermostat lead? How do we test the terminal?Where is the terminal located? We took off the front panel and do not see any buttons resembling the diagram in the manual.
The directions continue "Status LED will flash code and then turn ON the inducer motor.
What is the flash code?"

We would like to troubleshoot this and do the test - and are not able to find the component or do the test that the manual suggest.

Lastly what does the read light mean? Should we not be using our heater at this time?