1) Make sure youre already running -ve earth, otherwise it won't work (all altinators are neg earth apart from a handfull which are best stored in hens teath for protection)
2) Steel altinator brackets from series 3 engine (its easyer than making your own and should give perfect pulley alinement) and mount altinator.
3) remove all old dynamo wireing (ie the wires that go to the regulator box, you could ditch the regulator box as its now not needed but it should work fine if you leave it be.
4) wire warning lamp terminal directly to the dash lamp (other side of lamp powered my ignition circuit) and the other output terminals to the main battery wire on the starter selonoid.
5) Fit new fan belt made for landy with an altinator (I think dynamos use a different belt length)