# Editing a latex class file [closed]

I am new to Latex so I would like to ask you for some help, I was provided with a predefined class file (.cls) to fulfill the format requirements for my undergraduate thesis book and now I am trying to adapt a similar structure for my master thesis book.

The cls file without any modification is properly working in the Lyx environment for Latex. But once I slightly modify the cls file using the Notepad text editor, then the document doesn´t compile in LyX.

My question is how should I edit the contents of the class file, so it allows the document to be compiled? Do I need to compile the class file in a Tex editor? is it texWorks a good option?