Now there's a good question depends on the type.
high flush, low flush or close coupled ?
Replacing a close coupled ie: cistern sits on the back part of the toilet pan.
Rather than trying to explain go to www.simplyfiydiy.com
on left list click on bathrooms.
then fixtures
then middle list top one bathroom fixtures
then take it from there and select what you want to see.
then in middle list click replacing wc pan
Bob
April 2009