Hi Yusuf
I take it you mean you have a new ores site from the quickstart, looking the same as the ores demo site and now wish to edit the demo stuff replacing with your own?
If so, I’d suggest you spend a bit of time learning how Joomla works, Google has many tutorials on changing Joomla menus, adding/removing articles and learning how to use the administrator areas
Briefly, I’d suggest leaving the site structure with regard to modules, articles etc intact and one by one replacing the existing article text with your own, you change the article title at the top of the articlce then save it, This can be accessed from the article manager
after a few replacements you will see how Joomla works, this is the best way to work at first till you get familiar with Joomla.
Menus can be changed added to etc from the Menu Manager area
Use Google for info on how to do things if you are stuck, just use terms like Joomla 1.5 how to use menus, how to add articles, how to turn modules on/off
The scope is too big for me to give specific instructions here
Blessings Shannon