I am really sweating now

I recently figured out that coolant, refrigerant and freon are all the same thing. It is the liquid that goes into your cooling system. The air conditioner needs the liquid in order to work. Think of the AC like a car and the coolant being like oil. The machine needs it in order to survive. I know that my air conditioner is low on coolant. The AC unit has been flashing a red light at me indicating that something is wrong. The issue is that I don’t know what to do. Where do I buy coolant? Can I just pick up the necessary equipment at the local hardware store. After I get the liquid for the AC device, I don’t know where to put it. I’m guessing there is a designated spot in the air conditioner that the coolant has to go into. Again, like with a car, you put the oil in a certain location. You can’t just dump oil all over the hood or the seat. I read online and also found the wrong amount of liquid can damage the AC unit. If you use too much the air conditioner will work sluggishly and the liquid will leak out. You also will likely have mold, mildew or fungi form because of the added moisture. With too little of liquid, the machine will churn and burn. The equipment will grind together and hurt the mechanical workings. So I really want to make sure I do the cooling repair the correct way. Google has not been very helpful with it at all.

air conditioning tune-up