The response below seems to me to be not very useful for the original
poster.
The way to start a text document is to select File > New > Text Document.
(That's the "File" menu, "New" menu item, and "Text Document" in the
submenu.)
The way to change the margins is to select Format > Page..., and t
Just write a page like a letter,
And save in HTML format.
Then find a server that will share your website, preferably a free server,
it's the most difficult.
Lose your HTML file there, remember that it has the name Index.html.
Choose such a server so that uploading your site from your computer