you can get html of any web page ,
if it is present on net ,
then go to webpage right click on that , click on view source ,
put your html code by finding the perfect place , where you want to insert it , then save it.
if the file save on your pc ,
you can upload it to your web server by ftp.
or any ftp client such as filezilla ,
if you were running webserver at your home ,
the same works for that ,
open the webpage in your browser & repeat the same.
you just want to know a little knowledge of html ,
it is good to use any software ,
but learning makes you improve to your future tasks better .
such if you want to put a advertisement in the centre of any width from top & sides ,
just html will something look
--- html code takes efect , code text can't be shown ---
you can go to any w3schools to learn some codes.