Release drop link (1 bolt minimum), release suspension leg (2 Bolts), release top mount under bonnet (1 bolt). whole leg is now released.
Away from car, undo the next top bolt on the leg to release the old spring, i assume there will be no pressure with the spring being broken. Compress the new spring and put in place, reassemble the top of the leg (mount and bolt) now uncompress the spring making sure it sits in the grooves where it sits at the bottom. Now refit the whole leg using reversal of above. Top mount under bonnet, then 2 leg bolts, then drop link.
The same basic process is used for changing shocks, just shock change instead of spring.
Can take time, but its not rocket science!
Darrell, February 2010