No need to put the handles on, you want to lay the mold so that the two halves are together and the pins are seated to one another. I lay mine on its side in a little toaster over I got from the thrift store for a couple bucks, but I've used a hot plate as well. I just like the little oven because I can set the temp and put the timer on. I've heated all my molds to 400 degrees for 4 to 6 cycles for thirty minutes apiece and had good results. The only thing I disagree with Al's directions is the smoking of the mold after seasoning. I'm sure there is going to be some serious disagreement with me here, but the smoking of a mold is not necessary.
I have always "seasoned" bullet molds by pouring hot lead into them, and dumping the castings out.They rarely seem to produce good castings before 3-4 hot cool cycles.The hot cool cycles cook the machining fluids out of the pores of the mold.Any cavity where the casting sticks gets its edges rubbed with a popsicle stick to remove burrs.By starting a new mold with just enough use to get to casting temperature several times over you get to work any problems out. Any cavity where the casting sticks gets its edges rubbed with a popsicle stick to remove burrs. A magnifying glass is of great help in burr removal.