Where Did I go Wrong?

I hosted a teach a friend to homebrew day on Saturday that turned out horrible. Can someone tell me where I went wrong?

I heated 3.5 gallons of water to about 168. I added grains to the water (about 13 lbs of grains). I heated the grains in the pot until they were about 152 and stirred to make sure there were no clumps. I then transferred the entire grains and water to my Igloo cooler (mash Tun) I added some hot water to the mash tun so i could stir the grains in the mash tun (about 1/2 gallon to a gallon). I waited for an hour, and then ried to drain the wort off into my brew kettle. It drained about 1/2 gallon then stopped. I thought my false bottom had gotten clogged so I transferred the wort and grains to a secondary strainer. That strainer had too small of holes in order to drain liquid. I used another strainer to go back to brew kettle. By that times the grains were very soggy. I had to hand ladle them through a strainer just to get some liquid out of them. my 5 gallon batch ended up with about 2-2.5 gallons after brewing.

Heres where I think i went wrong. I think I let the grains in the hot water too long and then let them stay in the mash tun too long as well. The grains got too saturated and therefore were hard to drain, which in turn clogged the false bottom.
Am I right?

My first teach-a-friend-to-homebrew day also featured my first stuck sparge. To make matters worse, I found out afterwards that my thermometer was defective and reading 9 degrees high (first iodine test after an hour came out bad, had to mash for 2.5 hours). The whole ordeal took 11 hours from milling to cleanup, and my efficiency was somewhere around 50%.

I would recommend reading through all the all-grain section of HowToBrew, and reading through the sticky threads in the All Grain forum.