Easy to do, change the tensioner as well at same time just to be safe.
The hardest part is often getting the bottom pulley off or it's bolt undone.
4wd ones seem a lot more trouble than 2wd in this respect, as they seem to have some super tight pulleys.
It is merely a case of aligning the marks on the pulley, which is the LUG NOT the notch, then align so both cams pointers face towards each other, left one at 3 o'clock, right at 9 o'clock, then make sure the rotor arm is directly centred on the scribe mark on the dizzy body.
tabetha