Here is how you can edit a page:
If you want to put manual title,meta description or keywords, you have to put the code below
<!-- |PageTitle|MetaDesc|MetaKwords| -->
where PageTitle is the page title , MetaDesc is the meta description and ...
You can not put a '|' inside the PageTitle , MetaDesc ... as the symbol is used to seperate those.
After that lines, you have to put Markdown text that would be rendered.
The index.txt file is the most important file. The file is rendered and shown when a visitor visits your website's homepage.