91 Nissan Terrano 27TD Engine Mounts

If its the same as anyother car,

undo both 1/2s of the old mounts
Trolley jack under sump...
Block of wood on jack,
Jack up gently till the mounts are clear
remove FUBAR mount
put new mount in
lower motor
do up bolts
drive way
Check bolts again in a week.

That's how I replaced the torn mount on my T2 about a month ago, except I used a bottle jack as I don't have a trolly jack. Quite easy really.

Tips though is to have the front of the vevicle on chassis stands as it tends to get a bit dodgy when you take the weight of the motor on the jack and the front suspension unloads. I had the jack spit out at me before I discovered that. I was just lucky I was getting another spanner out of the tool box, still had the old mount in there and not my fingeres at the time.

Yeah pretty easy, a regular saturday night event if you own a Feroza. LOL Don't know how but they rip those huge rubber mounts to peices on the passenger side regulary!
We use a $50 trolly jack from supercheap, we actually lift the motor by the bell housing purly because of the shape of the feroza sump and it's a pretty small and light motor with a huge gear box on it.
If you've never done one before and you can access the mounts easy enough (would hate to do one on my 1kz-te) should take you and a mate about 20 minutes.

But I would be putting some axel stands under the vehicle as well so if the jack does poop itself or slip the axel stands would hopefully give you a little more height and stop anything from hitting you if your under the car.
The best way to do it is to lift the front up with the jack by the wish bones or similar, put the axel stands under, then lower the jack and use it to jack the motor, that way it will also give you some extra height under there for working. If the jack fails, it'll probally only be a couple of mm if that for it to lay rest on the axel stands.