Easy.. Remove the trim above the rear side windows.  Prop the hatch up
with something, and then unclip the old ones and install the new.  

I used some aftermarket ones, which only have one problem:  I think
the originals had some built-in damping to slow the opening rate, The
new ones let the hatch rise very quickly, so you have to keep it under
control and not just lift and let go.  
--
Email reply: please remove one letter from each side of "@"
Spammers are Scammers. Exterminate them.