We do not have a service manual for either the 430 or the 590. However there is a detailed thread about dismantling those mowers (which are very similar to each other) here:
https://www.outdoorking-forum.com.au/forum/ubbthreads.php?ubb=showflat&Number=22699&page=1

You will notice from the thread that it may not be the clutch that has failed: that machine is extremely prone to having its nylon roller-drive gear detach itself from its hub, resulting in a failure to drive the roller. If that has occurred you will need to consider replacing the plastic gear. Details are proviced in the thread.