Buy some of that blue painters tape, and tape up all the bits that might come into contact as you install,
the rear fender as you negotiate it into place between the sides
the front fender as you slide it between the forks,
AND when you go to do the tank, be sure to have your handle bars out of the way and either secured or padded with a towel so they don't flop onto your tank..
ive had mine apart a few times, but just relax and take it slow and no damage will occur.