the transmission has to be removed. it is very labor intensive and not something to do at home. you need a lift, air tools, and the frame has to be dropped.
it runs around 599-750 at a shop and well worth the money.
If you just want to see what's involved, Autozone have some popular workshop manuals for free on line once you register (for free) on their website http://bit.ly/autozone_repair_info.
and get an online repair manual subscription.
Hyundai as a car manufacturer put a lot of free technical information and workshop manuals on line for Hyundai owners. Check out www.hmaservice.com lots of great information.
As Roy said its a difficult job to do at home, not something to be taken on lightly.