I unfold them and get them into a circular shape, then work one side of the bead around the rim to mount it, so the rim helps give it shape. It is pretty much the same exact process as mounting a wire bead tire, except you need to help give the tire a bit more shape. Some patience and determination helps as well at times, but almost all of them get there eventually.
To be honest, I don't see how you snapped tire levers and pinched tubes, unless the tires you mounted were a very tight fit on that particular rim, which would have nothing to do with the shape the tire came to you in.
If the tire is too tight, I've heard of folks setting the tires out in the sun or placing them in their dryer (for laundry) to heat them up a bit to make them a bit more flexible and compliant.
To be honest, I don't see how you snapped tire levers and pinched tubes, unless the tires you mounted were a very tight fit on that particular rim, which would have nothing to do with the shape the tire came to you in.
If the tire is too tight, I've heard of folks setting the tires out in the sun or placing them in their dryer (for laundry) to heat them up a bit to make them a bit more flexible and compliant.