allow a weekend, just in case, it is an Alfa but took me just over half a (summers) day. Most screws are into plastic, so no real nightmare stuck threads to worry about.
The trickiest bit is getting the stupid quick release hose clip off as there is no room to quick release it. Also the new rad will not have this bit on it, so do not damage it in the process.
The DTE says take the bumper off, but I managed with out, however I did bend some of the mesh grille at the bottom out of the way to get at a couple of screws IIRC which saved me the bother, the mesh went back OK although a stickler may notice some slightly wobbly mesh.
Goes something like
Remove cross member trims
remove air intake tubing, MAF, air filter unit
remove bonnet catch
take off fan and frame
unscrew air con drier or some other bit and move to the side
unscrew air con rad from rad and support
undo what ever fixes rad to car,
undo bottom pipe, try to catch antifreeze, undo top pipe
hopefully the thing will lift out.
It was some five years since I did it so I may have missed some bits out, but in essence that's it. You will be shocked at how crap the old rad will be, the fan covers up most of the damaged areas, I thought mine was 10% gone,nearer 30-40%
Good luck with it