Hi Davidcot,
Use a soft faced or heavy rubber mallet to get it started, but don't hit it on the plate surface. As you tighten the flywheel bolts in a star fashion they will pull it on flush.
Maybe this will help.
http://www.cobraclub.com/html/cobra_28.shtml http://www.novak-adapt.com/knowledge/clutches_etc.htm
Regards
Chris