Michael, for researching your family in old Bohemia/Moravia at least you have to learn (a genealogical word pool) 3 languages: german, czech and latin
Here you have good informations for the beginning: https://www.familysearch.org/learn/wiki/en/Czech_Republic
And of course internet is full of further sources.
And you need really a lot of time for thumbing through the books.
I think, 10 Sept 1855 is not the correct birthdate of Katharina, if Georg Kryštof and Anna Fischer were her parents. Unfortunately I can not find the birth of Georg (with father Johann and mother Katharina Zelenka) in Taus/Domažlice about 1827 quickly with the index books.