Here are some sour mash directions for a 3 gallon batch.
Reserve about a cup of milled grains until you are done mashing.
Dough in with 6 # US 2-Row and .25# US Carapils into 8 Qt 165F water and rest for 60 mins, should stabilize around 150F for sacch rest.
When conversion is complete, stir in your reserved grains and cover the surface with foil to limit exposure to oxygen. I didn't photo this but you can imagine what a cup of milled grains sitting next to this pot would look like.
Cover and let sit at 100F+ for 24 hours. Here I'm using a heating pad from the local pharmacy set to high.
After 24 hours, heat sparge water to 180F. You will need about 10 qts of water at 180F. You are going to "tea bag" sparge this twice. See Deathbrewer's Easy All-Grain instructions.
When you remove the foil, you are going to see that air is trapped under your grains. The smell is sour milky. You may have a bit of rotten garbage smell in there, but the warmer you keep your sour mash, the better smelling it will be.
When you drain out your mash, you don't get very much wort out of it - it is sour, thick, juicy, and trapped on the grains. Here's what I got out of my first tea bag "runnings," I'm guessing about 3 qts. Thus your sparge water is nice and hot and you want to "tea bag" sparge twice - once in 6 qts and again in the last 4 qts of water.
Boil, hop, cool, aerate as usual