https://www.volvoforums.org.uk/showthread.php?t=284817
Not exactly a write-up but a few pictures from when I did mine.
Obviously you need to do the job from under the car. You should not need to remove the engine tray. You will need to drain the coolant. One of the hoses attaches straight to a drain spigot. Or use the one on the end of the radiator. You will almost certainly need to remove the oil filter for better access. If you aren’t due an oil change this can be done with only minimal loss of oil. Probably best to use new jubilee clips. I seem to have used 15-24mm and usually try to source stainless steel ones. There isn’t a lot of room so you cannot get away with using oversized clips. Good luck.