This is the site I used. It is free and operated by the Irish goverment.The civil records covers,
Births from 1864 to 1915.
Marriage from 1881 to 1940
Death from 1891 to 1965https://www.irishgenealogy.ie/en/
The record you view is the actual entry in the register. Margarets birth record gave me her name & dob,plus her parents names including the maiden name of the mother.
I then searched marriage records using only the surname Plunkett in the area of Claremorris.This gave 17 results for that name. Look through & found Kate Plunkett & Patrick Cunnane.
Click on their name then click image & view the record.
Hope this helps.