You take off the front bumper which is a big job in itself (remove the headlights which have a few screws and some clips, then undo all the bolts holding the front bumper on at the top, underneath the bumper and then either side there is a screw behind the splash-guard in the wheel arch) and then once that's off you can remove the front 'crossbar' to make things easier which has two bolts on it in the middle I think (??) and then from there you drain the radiator fluid and then unclamp the hoses and voila! Haven't done it in ages .... the last time I tried to upgrade my radiator it didn't go so well car overheated three times whilst test driving, the third time meant that fluid boiled over and fouled my camshaft position sensor which scared the Sugar Honey Iced Tea out of me because I thought I had seized the engine and the dying power when trying to move the car was the engine internals melting it was then I realized how important a working radiator fan is and that maybe I didn't need a bigger radiator after all
If you do get stuck with any certain bits then make a post here and I will gladly assist you