Is this info still required ?
There is a video which sounds like it may help
http://www.youtube.com/watch?v=D00FcmgXxb8Note that I haven't watched it...
Starting a bike which no-one is familiar with can sometimes be very tricky !
I've heard of folks selling them in despair.
Yes, the magneto lever should be part retarded for starting - assuming it pulls the timing full advanced for normal running, you set it back a bit.
Yes, if there is a choke lever - for normal running you pull it full up - you should feel it pull the choke slides up. For starting, drop them back down a bit - full down will probably be too much.
The valve lifter, which is normally near the clutch lever (but a shorter lever) is squeezed, and the kick starter gently pressed down - you should feel a piston go over top dead centre, and then the pressure comes off the kickstarter. Continue to squeeze the lever, and press down again on the kickstarter. Doing this, you find that you get 2 compressions in fairly close succession, then a long period where the flywheels can easily be turned over. The idea is to just ease over the second compression, stop squeezing the valve lifter, and then give a hefty kick to try and start it. This gives a l-o-n-g period of flywheel rotation to build up momentum during the kickstart kick, which should bounce it over compression, fire up and keeping running.
If this is too vague, can go into more detail.
Someone who is familiar with starting a big single should be able to help here too, its just a matter of finding the right crank position to start it. Setting the controls. And that long swinging kick.
Have fun.