if you don't know what you're doing, best get someone to do it.
It's not technically difficult, but it's a pain in the arse, and most of the bolts have probably never been removed before.
Jack car up and support rear with jackstands, You have to unbolt the tail shaft, and both half shafts, then unbolt the mounting bolts for the diff. If you have hicas i think the hicas rack gets in the way, so u have to unbolt that also.
Make sure you support the diff with a jack, as it's bloody heavy, and don't drop it on yourself.
once you have the diff housing, you need to take off the end cover, drain the fluid, removing the side shafts from the diff can be a pain, have to unbolt the two thingos that hold the diff centre in, then pry centre out with a crowbar or something.....
then put it all back together, make sure you use liquid gasket or something to seal the end cover on the housing.. and put it all back together again!
perhaps not for the weak harted, though if you know a back-yard mechanic, probably charge u $100 to do the changeover. a workshop will probably charge 200 or so perhaps. (i asked a workshop out of interest how much to weld up my stock lsd, and got quoted $300 to remove diff and weld it up)