I just publish an `asp.net` website then i made changes in its source code i added two `.aspx` files and then publish it again

The question is what I need to make this changes take effect on server. Do I have to replace all files or i can just **add** specific file?

I'm trying to add two `aspx` pages to the site that already exist on the server 
and want to know which file i have to add beside the ordinary `aspx` file to take effect on site

Thanks