Simple. Turn on your oven to the lowest setting. Put your water in the spaghetti pot according to how much grain you're using (Beersmith is great to calculate it for you) and put it on the stove. Once it's at your strike temp (Beersmith again) turn of the heat dump in your grains and stir.
Check the temp and adjust with either ice cubes or hot water from the microwave. If you do it right, you won't need much if any adjustment. Then stick the pot in the oven and turn the oven off. The residual heat will keep the mash at the target temp.
About a half hour later, turn the oven back on to the lowest setting while you take the pot out and give it a stir. Put it back in and turn the oven back off. Get another pot and start warming up your sparge water (you got it... Beersmith tells you that too).
When you're done mashing (an hour, usually) you're ready to collect your wort and sparge. Depending on how much grains your using, I used two methods....
If I'm using a small amount of grains, just pour it through the strainer into your kettle and let the strainer catch the grains. Then dump the grains back into your spaghetti pot and add your sparge water. Give it a stir, let it sit for a few minutes and then pour that into your kettle through the strainer too.
With more grains, like with my chocolate oatmeal stout, there's too much for the strainer to handle. That one FILLED the pasta pot to the top with grain and water. When that happens, I ladle the grains and wort into the strainer over the kettle. When the strainer is full, then I run some of my sparge water over it to "rinse" it. Once your down far enough to pour, start pouring it through the strainer, stopping to rinse it with some more of your sparge water when the strainer is full. That's a bit more involved than what I did with smaller amounts of grains, so that's why I moved to the igloo cooler. MUCH easier.