I have just finished brewing Ed's Hause Pale Ale using the same method you are talking about. Here is the steps that I took as far as I can remember.
1. Heated up 14qts of water to 176 degrees.
2. Put water in un-modded 5 gallon cooler.
3. Let water set until the temp dropped to 168 degrees.
4. Added half of the grain and stirred
5. Added the rest of the grain and stirred again.
6. Put lid on cooler and covered with a blanket.
7. Drank a homebrew
8. After an hour mash I heated up 12 qts sparge water to 190 degrees
9. After 90 minutes, I drained the wort from the cooler into my pot using an auto-siphon
10. Added half the sparge water to cooler after draining mash, let sit for 10 minutes, stirred and drained with auto-siphon and added the rest of the sparge water and waited for another 10 minutes.
11. Drained rest of sparge water, pulled up the bag of grain and sat it ontop of a cullinder and let drain for a few minutes. Put all liquer in my pot and boiled as per schedule.
This was only my second all grain batch but the first one using the cooler. I was one degree high on my mash temp, and a little low on sparging. My pre-boil gravity was 1.049 and ended up with OG of 1.055.
Like I said, this was only my second try at this, and some things need to be improved on but it seemed to work out ok.
Hope this helps.
