Not a big deal.
Pull the clutch off. Actually, you don't need to
pull the clutch off. Just remove the bolt and slide
the outer half off.
Then using the button holders, slide the outer
cup off.
You'll find the spring held on by a cover with 3 allen
screws in the clutch piece with the sheeve.
Put a BIG long bolt in a vise facing upwards. Put
large washers on the bottom and put the bolt
through the clutch. Now put a washer and nut on the
top and tighten it down on the cover.
Take out the allen screws. Then unscrew the nut
from the long bolt and remove the cover.
Replace spring and do the entire thing in reverse.
10-15 minutes tops - once you get the hang of it.