I Froze My 35mm Camera Last Night. What Do I Do To Warm It Back Up?

First of all do not not put it on any direct heat source, as it will damage it.
Rather, put it on a warm place, for example on top of the fridge at the back near the ventilation grid, for a while. That should thaw it out. Or above the radiator in your house, but not directly on it. You could also put your hairdryer on the cold setting and try to blow it dry. Not on the hot setting it may melt some parts.

You could follow the cat, if you have one, they will always seek out the warmest place and that's where it can thaw out. Wipe any moisture away as it melts, and blow on it to clear it.

Take the batteries out wait a few secs then put them back in.

This is probably too late.
First, before bringing the frozen camera indoors, put it in an air-tight plastic bag. The condensation from the moisture inside the house will do more harm than anything else. Now let it warm up slowly inside the bag. Depending on how old your camera is, you may run the risk of ruining the electronics due to moisture, cracking the seals and shifting the lens elements due to too fast expansion of the air and the seating material and the differential expansion of different materials (glass/metal/plastic). Slow does it.

Oh, do the same when you bring in film, and other delicate equipment, such as binoculars, electronics---protect from moisture condensation at all cost.