OK, been there done that, so I guess it falls to me to explain.
Get some MErc Boot seal goop, and large hose clamps that will
fit loosely into each bellows gap. Do this only on land, not
in the water.. Loosen clamps on both ends of boot.
Release boot from both ends. Remove 2 opposite circlips
from rear u-joint. Use a large socket and a small soket and a
small hammer to drive off end caps. DO NOT DAMAGE u-joints. Walk
new boot on re-install u-joint and circlips, grease u-joints, and
start with those hose clamps. Put 1 on each dip in the
bellows and tighten tham to extend the boot. It really works,
go slow, use the goop and check yourself each step of the way.
I did it in about 2 hours and had to replace a circlip and
had to figure out the hoseclamp jig. Good luck
Drift-R-Cruise 30 Ft forever. Remeber buy one size too small and outfit the way you like it!