hi, first when i do them i loosen of the four pulley mounting bolts then take the belt off,then from behind undo the high pressure hose pipe with a good spanner or pipe spanner they can be tight, dont use a cheap ass spanner last thing you wanna do is round it off,take the pulley off undo the supply hose have a drain bucket underneath then the two mounting bolts.
when going back on i fit a new o ring to the high pressure hose the screw it all the way into the pump by HAND making sure it not cross threaded, then fit the two pump mount bolts tigthen them up then tighten the high pressure hose,but not to tigh as you can distort the hole nut then it will leak, refit supply hose fill up with oil refit pulley then belt then tighten the pully.
good luck let us know how you go.
pete.