Chevrolet Repair: Radiator flush, monte carlo z34, radiator cap

Question
Im going to clean out my 1998 Monte Carlo Z34's radiator and coolant container by myself. I was told (because its dirty) to clean out the plastic container with sand to get all the grit out and thoroughly wash the sand out. Then to flush the radiator with the cleaner fluid I picked up using the directions on the back. Afterwards Im supposed to mix half coolent and half water into the container, turn the engine on and continue to fill untill I reach the "hot" line. Is there anything wronge with what im about to do? and if not, are there any other tips you can give me since im new to doing things myself and only do it cause I cant afford a mechanic?

Answer
First, don't put sand in the resovoir bottle.
Second, make sure that your vehicle manufacturer specifies what coolant to use.
((mixing wrong fluids can create an acid and eat the metal off of everything it touches.
Third, I would personally replace the thermostat while your flushing it out. Then I would attach a flush valve that installs fairly easily to your heater hoses. Once the thermostat was removed, I would flush it then.
If your engine doesn't have a purge screw, then I would fill it up, start it and wait for the fluid in the radiator to start to flow or get warm.
Other than that, no, I see nothing wrong with what your attempting. Consider also replacing radiator cap and hoses if possible.