When i turn on the heat, the fan to my outside unit will not kick on, therefor will not produce any heat through the vents

Mistake #1, calling the plumber/installer to diagnose a heating problem; unless of course he was dually licensed as a plumber and a HVACR technician. (Heating, Ventilation, Air-Conditioner, Refrigeration)
I would contact the plumber/installer in case of parts / unit warranty or installation issues since you purchased it and had it installed by him.
Your unit has a combustion motor with a "squirrel cage" type fan attached to it.
The purpose of the combustion motor-fan unit is threefold; it acts to purge (exhaust) out any gas build-up before ignition occurs; it pulls outside air (oxygen) in through the intake pipe which is needed for flame ignition and to maintain it; while at the same time - vents spent/toxic gases out the flue pipe.
There is also one convection fan motor controlling two convection "squirrel cage" type fans. It's purpose is to circulate the heated air created by the heat exchanger, into the room.
On initial start-up, it is the combustion motor/fan unit that kicks in, so if you are hearing the noise at this start up phase, this would be the source of your problem.
The convection fan motor doesn't kick in until there is a heat rise sensed by the low-limit switch; meaning, If the blower came on at the same time as the burner, it would pump cold air through the house at first. The limit switch includes a sensor in the heat exchanger to determine when the air is warm enough to circulate. Once the air reaches a preset temperature, the limit switch turns on the blower.
Therefore if you hear the squealing sound when the convection blower turns on, that would be the source of the problem.
Why would the noise occur, most likely the sealed bearings in the motors are going bad; or perhaps the fan blades are loose and wobbly; or something got inside the fan housing and is chaffing.
A major cause of early, premature combustion fan motor wear is improper installation of the flue pipe; condensation flow back to the motor will damage it
Another reason, manufacturer defect in the motor; it happens.

The bearings are bad in the motor and after the fan runs enough it eventually gets hot, making the bearing screech and the fan locks up. Need to replace motor again. See if it has a warranty. The reason it gets hot is because the fan is what removes the heat from the coil and if the fan isn't running there is nothing to cool it off so to speak.

You can cover the system as long as the vent is clear if this is a gas package unit & not a heat pump.

relay module, compressor going out on safety change capacitors

The blinking light is because the unit is waiting for the outdoor unit to come on. If in heating mode, the indoor fan will not run before enough pressure and therefore heat has built up. You should check that the indoor air return sensor is not faulty and therefore preventing the outdoor unit from coming on.

Turn Tsat to fan to see if inside unit will come on. If it does Tstat needs replaced. If not it is fan motor or fan relay. Possible cap. Do you here the fan relay come in. If it is a Good man unit it is time delay and you wont here it. Need to know your make of unit. Rusty

you have a heat pump which removes heat from outside air when it is too cold out below 30* the unit can no longer produce heat and electric strip heaters kick in

Try turning the power off at the fuse box, waiting 5 minutes turning the system back on and spray some water on the vents on the side of the outside condenser. If the fan isnt spining get a twig and spin it in an anti-clockwise direction after 1 or 2 spins it should start spinning on its own. continue to hose the vents with water for another 5 minutes. Its important to have the fan spinning as it extracts the heat from the condenser box.

replace the control unit.